--- /dev/null
+++ Libc/Libc-1725.0.11/sys/fork.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2010 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <TargetConditionals.h>
+#include <stdbool.h>
+
+#include "_libc_init.h" // for libc_atfork_helper
+
+extern pid_t __fork(void);
+extern pid_t __vfork(void);
+
+static void (*_libSystem_atfork_prepare)(void) = 0;
+static void (*_libSystem_atfork_parent)(void) = 0;
+static void (*_libSystem_atfork_child)(void) = 0;
+static void (*_libSystem_atfork_prepare_v2)(unsigned int flags, ...) = 0;
+static void (*_libSystem_atfork_parent_v2)(unsigned int flags, ...) = 0;
+static void (*_libSystem_atfork_child_v2)(unsigned int flags, ...) = 0;
+
+__private_extern__
+void _libc_fork_init(const struct _libc_functions *funcs)
+{
+	if (funcs->version >= 2) {
+		_libSystem_atfork_prepare_v2 = funcs->atfork_prepare_v2;
+		_libSystem_atfork_parent_v2 = funcs->atfork_parent_v2;
+		_libSystem_atfork_child_v2 = funcs->atfork_child_v2;
+	} else {
+		_libSystem_atfork_prepare = funcs->atfork_prepare;
+		_libSystem_atfork_parent = funcs->atfork_parent;
+		_libSystem_atfork_child = funcs->atfork_child;
+	}
+}
+
+static inline __attribute__((always_inline))
+pid_t
+_do_fork(bool libsystem_atfork_handlers_only)
+{
+	int ret;
+
+	int flags = libsystem_atfork_handlers_only ? LIBSYSTEM_ATFORK_HANDLERS_ONLY_FLAG : 0;
+
+	if (_libSystem_atfork_prepare_v2) {
+		_libSystem_atfork_prepare_v2(flags);
+	} else {
+		_libSystem_atfork_prepare();
+	}
+	// Reader beware: this __fork() call is yet another wrapper around the actual syscall
+	// and lives inside libsyscall. The fork syscall needs some cuddling by asm before it's
+	// allowed to see the big wide C world.
+	ret = __fork();
+	if (-1 == ret)
+	{
+		// __fork already set errno for us
+		if (_libSystem_atfork_parent_v2) {
+			_libSystem_atfork_parent_v2(flags);
+		} else {
+			_libSystem_atfork_parent();
+		}
+		return ret;
+	}
+
+	if (0 == ret)
+	{
+		// We're the child in this part.
+		if (_libSystem_atfork_child_v2) {
+			_libSystem_atfork_child_v2(flags);
+		} else {
+			_libSystem_atfork_child();
+		}
+		return 0;
+	}
+
+	if (_libSystem_atfork_parent_v2) {
+		_libSystem_atfork_parent_v2(flags);
+	} else {
+		_libSystem_atfork_parent();
+	}
+	return ret;
+}
+
+pid_t
+fork(void)
+{
+	return _do_fork(false);
+}
+
+pid_t
+vfork(void)
+{
+	// vfork() is now just fork().
+	// Skip the API pthread_atfork handlers, but do call our own
+	// Libsystem_atfork handlers. People are abusing vfork in ways where
+	// it matters, e.g. tcsh does all kinds of stuff after the vfork. Sigh.
+	return _do_fork(true);
+}
+