lib/libc/gen/_once_stub.c

   1 /*-
   2  * Copyright (c) 2009 Advanced Computing Technologies LLC
   3  * Written by: John H. Baldwin <jhb@FreeBSD.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD: head/lib/libc/gen/_once_stub.c 199614 2009-11-20 20:43:34Z jhb $
  28  */
  29
  30
  31 #include "namespace.h"
  32 #include <pthread.h>
  33 #include "un-namespace.h"
  34 #include "libc_private.h"
  35
  36 /* This implements pthread_once() for the single-threaded case. */
  37 static int
  38 _libc_once(pthread_once_t *once_control, void (*init_routine)(void))
  39 {
  40
  41         if (once_control->state == PTHREAD_DONE_INIT)
  42                 return (0);
  43         init_routine();
  44         once_control->state = PTHREAD_DONE_INIT;
  45         return (0);
  46 }
  47
  48 /*
  49  * This is the internal interface provided to libc.  It will use
  50  * pthread_once() from the threading library in a multi-threaded
  51  * process and _libc_once() for a single-threaded library.  Because
  52  * _libc_once() uses the same ABI for the values in the pthread_once_t
  53  * structure as the threading library, it is safe for a process to
  54  * switch from _libc_once() to pthread_once() when threading is
  55  * enabled.
  56  */
  57 int
  58 _once(pthread_once_t *once_control, void (*init_routine)(void))
  59 {
  60
  61         if (__isthreaded)
  62                 return (_pthread_once(once_control, init_routine));
  63         return (_libc_once(once_control, init_routine));
  64 }