better fork

ev.c

@@ -155,21 +155,24 @@ volatile double SIGFPE_REQ = 0.0f;
 
 /*****************************************************************************/
 
-static void (*syserr_cb)(void);
+static void (*syserr_cb)(const char *msg);
 
-void ev_set_syserr_cb (void (*cb)(void))
+void ev_set_syserr_cb (void (*cb)(const char *msg))
 {
   syserr_cb = cb;
 }
 
 static void
-syserr (void)
+syserr (const char *msg)
 {
+  if (!msg)
+    msg = "(libev) system error";
+
   if (syserr_cb)
-    syserr_cb ();
+    syserr_cb (msg);
   else
     {
-      perror ("libev");
+      perror (msg);
       abort ();
     }
 }
@@ -380,7 +383,7 @@ fd_reify (EV_P)
 static void
 fd_change (EV_P_ int fd)
 {
-  if (anfds [fd].reify || fdchangecnt < 0)
+  if (anfds [fd].reify)
     return;
 
   anfds [fd].reify = 1;
@@ -428,7 +431,7 @@ fd_enomem (EV_P)
       }
 }
 
-/* susually called after fork if method needs to re-arm all fds from scratch */
+/* usually called after fork if method needs to re-arm all fds from scratch */
 static void
 fd_rearm_all (EV_P)
 {
@@ -695,6 +698,9 @@ loop_init (EV_P_ int methods)
 #if EV_USE_SELECT
       if (!method && (methods & EVMETHOD_SELECT)) method = select_init (EV_A_ methods);
 #endif
+
+      ev_watcher_init (&sigev, sigcb);
+      ev_set_priority (&sigev, EV_MAXPRI);
     }
 }
 
@@ -730,19 +736,34 @@ loop_destroy (EV_P)
   array_free (check, );
 
   method = 0;
-  /*TODO*/
 }
 
-void
+static void
 loop_fork (EV_P)
 {
-  /*TODO*/
 #if EV_USE_EPOLL
   if (method == EVMETHOD_EPOLL ) epoll_fork  (EV_A);
 #endif
 #if EV_USE_KQUEUE
   if (method == EVMETHOD_KQUEUE) kqueue_fork (EV_A);
 #endif
+
+  if (ev_is_active (&sigev))
+    {
+      /* default loop */
+
+      ev_ref (EV_A);
+      ev_io_stop (EV_A_ &sigev);
+      close (sigpipe [0]);
+      close (sigpipe [1]);
+
+      while (pipe (sigpipe))
+        syserr ("(libev) error creating pipe");
+
+      siginit (EV_A);
+    }
+
+  postfork = 0;
 }
 
 #if EV_MULTIPLICITY
@@ -771,7 +792,7 @@ ev_loop_destroy (EV_P)
 void
 ev_loop_fork (EV_P)
 {
-  loop_fork (EV_A);
+  postfork = 1;
 }
 
 #endif
@@ -804,8 +825,6 @@ ev_default_loop (int methods)
 
       if (ev_method (EV_A))
         {
-          ev_watcher_init (&sigev, sigcb);
-          ev_set_priority (&sigev, EV_MAXPRI);
           siginit (EV_A);
 
 #ifndef WIN32
@@ -848,15 +867,8 @@ ev_default_fork (void)
   struct ev_loop *loop = default_loop;
 #endif
 
-  loop_fork (EV_A);
-
-  ev_io_stop (EV_A_ &sigev);
-  close (sigpipe [0]);
-  close (sigpipe [1]);
-  pipe (sigpipe);
-
-  ev_ref (EV_A); /* signal watcher */
-  siginit (EV_A);
+  if (method)
+    postfork = 1;
 }
 
 /*****************************************************************************/
@@ -1044,6 +1056,10 @@ ev_loop (EV_P_ int flags)
           call_pending (EV_A);
         }
 
+      /* we might have forked, so reify kernel state if necessary */
+      if (expect_false (postfork))
+        loop_fork (EV_A);
+
       /* update fd-related kernel structures */
       fd_reify (EV_A);
 

ev.h

@@ -241,7 +241,7 @@ void ev_set_allocator (void *(*cb)(void *ptr, long size));
  * retryable syscall error
  * (such as failed select, poll, epoll_wait)
  */
-void ev_set_syserr_cb (void (*cb)(void));
+void ev_set_syserr_cb (void (*cb)(const char *msg));
 
 # if EV_MULTIPLICITY
 /* the default loop is the only one that handles signals and child watchers */

ev_epoll.c

@@ -57,7 +57,7 @@ epoll_poll (EV_P_ ev_tstamp timeout)
   if (eventcnt < 0)
     {
       if (errno != EINTR)
-        syserr ();
+        syserr ("(libev) epoll_wait");
 
       return;
     }
@@ -110,7 +110,16 @@ epoll_destroy (EV_P)
 static void
 epoll_fork (EV_P)
 {
-  epoll_fd = epoll_create (256);
+  for (;;)
+    {
+      epoll_fd = epoll_create (256);
+
+      if (epoll_fd >= 0)
+        break;
+
+      syserr ("(libev) epoll_create");
+    }
+
   fcntl (epoll_fd, F_SETFD, FD_CLOEXEC);
 
   fd_rearm_all (EV_A);

ev_kqueue.c

@@ -87,7 +87,7 @@ kqueue_poll (EV_P_ ev_tstamp timeout)
   if (res < 0)
     { 
       if (errno != EINTR)
-        syserr ();
+        syserr ("(libev) kevent");
 
       return;
     } 
@@ -185,7 +185,16 @@ kqueue_destroy (EV_P)
 static void
 kqueue_fork (EV_P)
 {
-  kqueue_fd = kqueue ();
+  for (;;)
+    {
+      kqueue_fd = kqueue ();
+
+      if (kqueue_fd >= 0)
+        break;
+
+      syserr ("(libev) kqueue");
+    }
+
   fcntl (kqueue_fd, F_SETFD, FD_CLOEXEC);
 
   /* re-register interest in fds */

ev_poll.c

@@ -85,7 +85,7 @@ poll_poll (EV_P_ ev_tstamp timeout)
       else if (errno == ENOMEM && !syserr_cb)
         fd_enomem (EV_A);
       else if (errno != EINTR)
-        syserr ();
+        syserr ("(libev) poll");
 
       return;
     }

ev_select.c

@@ -96,7 +96,7 @@ select_poll (EV_P_ ev_tstamp timeout)
       else if (errno == ENOMEM && !syserr_cb)
         fd_enomem (EV_A);
       else if (errno != EINTR)
-        syserr ();
+        syserr ("(libev) select");
 
       return;
     }

ev_vars.h

@@ -10,6 +10,7 @@ VARx(ev_tstamp, method_fudge) /* assumed typical timer resolution */
 VAR (method_modify, void (*method_modify)(EV_P_ int fd, int oev, int nev))
 VAR (method_poll  , void (*method_poll)(EV_P_ ev_tstamp timeout))
 
+VARx(int, postfork)  /* true if we need to recreate kernel state after fork */
 VARx(int, activecnt) /* number of active events */
 
 #if EV_USE_SELECT || EV_GENWRAP