Add unregistering atfork handlers on dlclose

* sysdeps/generic/fork.h: New file.
* forward.c: Include <fork.h>.
(__unregister_atfork): New function.

2 files changed, 61 insertions, 1 deletions

diff --git a/forward.c b/forward.c
index 79b2bec..af1d2c4 100644
--- a/forward.c
+++ b/forward.c
@@ -22,6 +22,7 @@
 #include <stdlib.h>
 #include <shlib-compat.h>
 #include <pthread-functions.h>
+#include <fork.h>
 
 /* Pointers to the libc functions.  */
 struct pthread_functions __libc_pthread_functions attribute_hidden;
@@ -245,4 +246,34 @@ __register_atfork (
   return 0;
 }
 
-/* TODO: unregister_atfork, and define UNREGISTER_ATFORK, for module unload support */
+void
+__unregister_atfork (void *dso_handle)
+{
+  struct atfork **handlers, *prev = NULL, *next;
+  __mutex_lock (&atfork_lock);
+  handlers = &fork_handlers;
+  while (*handlers)
+    {
+      if ((*handlers)->dso_handle == dso_handle)
+	{
+	  /* Drop this handler from the list.  */
+	  if (*handlers == fork_last_handler)
+	    {
+	      /* Was last, new last is prev, if any.  */
+	      fork_last_handler = prev;
+	    }
+
+	  next = (*handlers)->next;
+	  if (next)
+	    next->prev = prev;
+	  *handlers = next;
+	}
+      else
+	{
+	  /* Just proceed to next handler.  */
+	  prev = *handlers;
+	  handlers = &prev->next;
+	}
+    }
+  __mutex_unlock (&atfork_lock);
+}
diff --git a/sysdeps/generic/fork.h b/sysdeps/generic/fork.h
new file mode 100644
index 0000000..c6ac15e
--- /dev/null
+++ b/sysdeps/generic/fork.h
@@ -0,0 +1,29 @@
+/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Function to call to unregister fork handlers.  */
+extern void __unregister_atfork (void *dso_handle) attribute_hidden;
+#define UNREGISTER_ATFORK(dso_handle) __unregister_atfork (dso_handle)
+
+
+/* C library side function to register new fork handlers.  */
+extern int __register_atfork (void (*__prepare) (void),
+			      void (*__parent) (void),
+			      void (*__child) (void),
+			      void *dso_handle);
+libc_hidden_proto (__register_atfork)