Libc-391.4.1.tar.gz

[apple/libc.git] / i386 / sys / getpid.s

diff --git a/i386/sys/getpid.s b/i386/sys/getpid.s
index 81833aea8d0689ef6e2e501010c79152434e4063..d08bd95236bd97ec4682ef9e785d4327b100dbe1 100644 (file)
--- a/i386/sys/getpid.s
+++ b/i386/sys/getpid.s
@@ -1,10 +1,8 @@
 /*
- * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1999-2003 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
- * 
  * 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
@@ -27,5 +25,42 @@
  */
 #include "SYS.h"
 
-UNIX_SYSCALL(getpid, 0)
-       ret             // pid = getpid();
+       .data
+       .private_extern __current_pid
+__current_pid:
+       .long 0
+L__current_pid_addr = __current_pid
+
+#if defined(__DYNAMIC__)
+#define GET_CURRENT_PID                                \
+       call    0f                              ; \
+0:                                             ; \
+       popl    %ecx                            ; \
+       leal    L__current_pid_addr-0b(%ecx), %ecx
+
+#define __current_pid (%ecx)
+
+#else
+#define GET_CURRENT_PID
+#endif
+
+/*
+ * If __current_pid is > 0, return it, else make syscall.
+ * If __current_pid is 0, cache result of syscall.
+ */
+TEXT
+LEAF(_getpid, 0)
+       GET_CURRENT_PID
+       movl            __current_pid, %eax
+       testl           %eax, %eax
+       jle             1f
+       ret
+1:
+       UNIX_SYSCALL_NONAME(getpid, 0)
+       movl            %eax, %edx
+       xorl            %eax, %eax
+       GET_CURRENT_PID
+       lock
+       cmpxchgl        %edx, __current_pid
+       movl            %edx, %eax
+       ret