3 files changed, 81 insertions, 2 deletions

diff --git a/src/lib/libc/include/atfork.h b/src/lib/libc/include/atfork.h
new file mode 100644
index 0000000000..8ec611098c
--- /dev/null
+++ b/src/lib/libc/include/atfork.h
@@ -0,0 +1,44 @@
+/*      $OpenBSD: atfork.h,v 1.1 2015/04/07 01:27:07 guenther Exp $ */
+
+/*
+ * Copyright (c) 2008 Kurt Miller <kurt@openbsd.org>
+ * Copyright (c) 2008 Philip Guenther <guenther@openbsd.org>
+ * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: /repoman/r/ncvs/src/lib/libc_r/uthread/uthread_atfork.c,v 1.1 2004/12/10 03:36:45 grog Exp $
+ */
+
+#include <sys/queue.h>
+
+struct atfork_fn {
+        TAILQ_ENTRY(atfork_fn) fn_next;
+        void    (*fn_prepare)(void);
+        void    (*fn_parent)(void);
+        void    (*fn_child)(void);
+        void    *fn_dso;
+};
+
+extern TAILQ_HEAD(atfork_listhead, atfork_fn) _atfork_list;
+
diff --git a/src/lib/libc/include/thread_private.h b/src/lib/libc/include/thread_private.h
index 673fb9c6a6..43ebf7d96e 100644
--- a/src/lib/libc/include/thread_private.h
+++ b/src/lib/libc/include/thread_private.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: thread_private.h,v 1.25 2011/10/16 06:29:56 guenther Exp $ */
+/* $OpenBSD: thread_private.h,v 1.26 2015/04/07 01:27:07 guenther Exp $ */
 
 /* PUBLIC DOMAIN: No Rights Reserved. Marco S Hyman <marc@snafu.org> */
 
@@ -160,6 +160,18 @@ void	_thread_atexit_unlock(void);
                                                 _thread_atexit_unlock();\
                                 } while (0)
 
+void    _thread_atfork_lock(void);
+void    _thread_atfork_unlock(void);
+
+#define _ATFORK_LOCK()          do {                                    \
+                                        if (__isthreaded)               \
+                                                _thread_atfork_lock();  \
+                                } while (0)
+#define _ATFORK_UNLOCK()        do {                                    \
+                                        if (__isthreaded)               \
+                                                _thread_atfork_unlock();\
+                                } while (0)
+
 void    _thread_arc4_lock(void);
 void    _thread_arc4_unlock(void);
 
@@ -172,4 +184,9 @@ void	_thread_arc4_unlock(void);
                                                 _thread_arc4_unlock();\
                                 } while (0)
 
+/*
+ * Wrapper for _thread_sys_fork()
+ */
+pid_t   _thread_fork(void);
+
 #endif /* _THREAD_PRIVATE_H_ */
diff --git a/src/lib/libc/stdlib/atexit.c b/src/lib/libc/stdlib/atexit.c
index 6532b382ea..a33080571f 100644
--- a/src/lib/libc/stdlib/atexit.c
+++ b/src/lib/libc/stdlib/atexit.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: atexit.c,v 1.20 2014/07/11 09:51:37 kettenis Exp $ */
+/*      $OpenBSD: atexit.c,v 1.21 2015/04/07 01:27:07 guenther Exp $ */
 /*
  * Copyright (c) 2002 Daniel Hartmeier
  * All rights reserved.
@@ -35,6 +35,7 @@
 #include <string.h>
 #include <unistd.h>
 #include "atexit.h"
+#include "atfork.h"
 #include "thread_private.h"
 
 struct atexit *__atexit;
@@ -161,6 +162,23 @@ restart:
                 __atexit = NULL;
         }
         _ATEXIT_UNLOCK();
+
+        /*
+         * If unloading a DSO, unregister any atfork handlers registered
+         * by it.  Skip the locking if the list is currently empty.
+         */
+        if (dso != NULL && TAILQ_FIRST(&_atfork_list) != NULL) {
+                struct atfork_fn *af, *afnext;
+
+                _ATFORK_LOCK();
+                TAILQ_FOREACH_SAFE(af, &_atfork_list, fn_next, afnext)
+                        if (af->fn_dso == dso) {
+                                TAILQ_REMOVE(&_atfork_list, af, fn_next);
+                                free(af);
+                        }
+                _ATFORK_UNLOCK();
+
+        }
 }
 
 /*