sysdeps/mach/libc-lock.h

   1 /* libc-internal interface for mutex locks.  Mach cthreads version.
   2    Copyright (C) 1996-2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _LIBC_LOCK_H
  20 #define _LIBC_LOCK_H 1
  21
  22 #ifdef _LIBC
  23 #include <cthreads.h>
  24 #define __libc_lock_t struct mutex
  25 #else
  26 typedef struct __libc_lock_opaque__ __libc_lock_t;
  27 #endif
  28
  29 /* Type for key of thread specific data.  */
  30 typedef cthread_key_t __libc_key_t;
  31
  32 /* Define a lock variable NAME with storage class CLASS.  The lock must be
  33    initialized with __libc_lock_init before it can be used (or define it
  34    with __libc_lock_define_initialized, below).  Use `extern' for CLASS to
  35    declare a lock defined in another module.  In public structure
  36    definitions you must use a pointer to the lock structure (i.e., NAME
  37    begins with a `*'), because its storage size will not be known outside
  38    of libc.  */
  39 #define __libc_lock_define(CLASS,NAME) \
  40   CLASS __libc_lock_t NAME;
  41
  42 /* Define an initialized lock variable NAME with storage class CLASS.  */
  43 #define __libc_lock_define_initialized(CLASS,NAME) \
  44   CLASS __libc_lock_t NAME = MUTEX_INITIALIZER;
  45
  46 /* Initialize the named lock variable, leaving it in a consistent, unlocked
  47    state.  */
  48 #define __libc_lock_init(NAME) __mutex_init (&(NAME))
  49
  50 /* Finalize the named lock variable, which must be locked.  It cannot be
  51    used again until __libc_lock_init is called again on it.  This must be
  52    called on a lock variable before the containing storage is reused.  */
  53 #define __libc_lock_fini(NAME) __mutex_unlock (&(NAME))
  54
  55 /* Lock the named lock variable.  */
  56 #define __libc_lock_lock(NAME) __mutex_lock (&(NAME))
  57
  58 /* Lock the named lock variable.  */
  59 #define __libc_lock_trylock(NAME) (!__mutex_trylock (&(NAME)))
  60
  61 /* Unlock the named lock variable.  */
  62 #define __libc_lock_unlock(NAME) __mutex_unlock (&(NAME))
  63
  64
  65 /* XXX for now */
  66 #define __libc_rwlock_define            __libc_lock_define
  67 #define __libc_rwlock_define_initialized __libc_lock_define_initialized
  68 #define __libc_rwlock_init              __libc_lock_init
  69 #define __libc_rwlock_fini              __libc_lock_fini
  70 #define __libc_rwlock_rdlock            __libc_lock_lock
  71 #define __libc_rwlock_wrlock            __libc_lock_lock
  72 #define __libc_rwlock_tryrdlock         __libc_lock_trylock
  73 #define __libc_rwlock_trywrlock         __libc_lock_trylock
  74 #define __libc_rwlock_unlock            __libc_lock_unlock
  75
  76
  77 /* Start a critical region with a cleanup function */
  78 #define __libc_cleanup_region_start(DOIT, FCT, ARG)                         \
  79 {                                                                           \
  80   typeof (***(FCT)) *__save_FCT = (DOIT) ? (FCT) : 0;                       \
  81   typeof (ARG) __save_ARG = ARG;                                            \
  82   /* close brace is in __libc_cleanup_region_end below. */
  83
  84 /* End a critical region started with __libc_cleanup_region_start. */
  85 #define __libc_cleanup_region_end(DOIT)                                     \
  86   if ((DOIT) && __save_FCT != 0)                                            \
  87     (*__save_FCT)(__save_ARG);                                              \
  88 }
  89
  90 /* Sometimes we have to exit the block in the middle.  */
  91 #define __libc_cleanup_end(DOIT)                                            \
  92   if ((DOIT) && __save_FCT != 0)                                            \
  93     (*__save_FCT)(__save_ARG);                                              \
  94
  95
  96 /* Use mutexes as once control variables. */
  97
  98 struct __libc_once
  99   {
 100     __libc_lock_t lock;
 101     int done;
 102   };
 103
 104 #define __libc_once_define(CLASS,NAME) \
 105   CLASS struct __libc_once NAME = { MUTEX_INITIALIZER, 0 }
 106
 107
 108 /* Call handler iff the first call.  */
 109 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
 110   do {                                                                        \
 111     __libc_lock_lock (ONCE_CONTROL.lock);                                     \
 112     if (!ONCE_CONTROL.done)                                                   \
 113       (INIT_FUNCTION) ();                                                     \
 114     ONCE_CONTROL.done = 1;                                                    \
 115     __libc_lock_unlock (ONCE_CONTROL.lock);                                   \
 116   } while (0)
 117
 118 /* Get once control variable.  */
 119 #define __libc_once_get(ONCE_CONTROL)   ((ONCE_CONTROL).done != 0)
 120
 121 #ifdef _LIBC
 122 /* We need portable names for some functions.  E.g., when they are
 123    used as argument to __libc_cleanup_region_start.  */
 124 #define __libc_mutex_unlock __mutex_unlock
 125 #endif
 126
 127 #define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
 128 #define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
 129 void *__libc_getspecific (__libc_key_t key);
 130
 131 /* XXX until cthreads supports recursive locks */
 132 #define __libc_lock_define_initialized_recursive __libc_lock_define_initialized
 133 #define __libc_lock_init_recursive __libc_lock_init
 134 #define __libc_lock_fini_recursive __libc_lock_fini
 135 #define __libc_lock_trylock_recursive __libc_lock_trylock
 136 #define __libc_lock_unlock_recursive __libc_lock_unlock
 137 #define __libc_lock_lock_recursive __libc_lock_lock
 138
 139 #define __rtld_lock_define_initialized_recursive __libc_lock_define_initialized
 140 #define __rtld_lock_fini_recursive __libc_lock_fini
 141 #define __rtld_lock_trylock_recursive __libc_lock_trylock
 142 #define __rtld_lock_unlock_recursive __libc_lock_unlock
 143 #define __rtld_lock_lock_recursive __libc_lock_lock
 144
 145 #endif  /* libc-lock.h */