Libc-763.11.tar.gz

[apple/libc.git] / sys / fork.c

diff --git a/sys/fork.c b/sys/fork.c
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+++ b/sys/fork.c
@@ -0,0 +1,73 @@
+/*
+ * 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>
+
+extern pid_t __fork(void);
+extern void _cthread_fork_prepare();
+extern void _cthread_fork_parent();
+extern void _cthread_fork_child();
+
+static void (*_libSystem_atfork_prepare)(void) = 0;
+static void (*_libSystem_atfork_parent)(void) = 0;
+static void (*_libSystem_atfork_child)(void) = 0;
+
+__private_extern__ void _libc_fork_init(void (*prepare)(void), void (*parent)(void), void (*child)(void))
+{
+       _libSystem_atfork_prepare = prepare;
+       _libSystem_atfork_parent = parent;
+       _libSystem_atfork_child = child;
+}
+
+/*
+ * fork stub
+ */
+pid_t
+fork(void)
+{
+       int ret;
+       
+       _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
+               _libSystem_atfork_parent();
+               return ret;
+       }
+       
+       if (0 == ret)
+       {
+               // We're the child in this part.
+               _libSystem_atfork_child();
+               return 0;
+       }
+       
+       _libSystem_atfork_parent();
+       return ret;
+}
+