sysdeps/mach/hurd/libc-lock.h

   1 /* libc-internal interface for mutex locks.  Hurd version using Mach cthreads.
   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 #if (_LIBC - 0) || (_CTHREADS_ - 0)
  23 #include <cthreads.h>
  24 #include <hurd/threadvar.h>
  25
  26 typedef struct mutex __libc_lock_t;
  27 typedef struct
  28 {
  29   struct mutex mutex;
  30   void *owner;
  31   int count;
  32 } __libc_lock_recursive_t;
  33 typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
  34
  35 #define __libc_lock_owner_self() ((void *) __hurd_threadvar_location (0))
  36
  37 #else
  38 typedef struct __libc_lock_opaque__ __libc_lock_t;
  39 typedef struct __libc_lock_recursive_opaque__ __libc_lock_recursive_t;
  40 #endif
  41
  42 /* Define a lock variable NAME with storage class CLASS.  The lock must be
  43    initialized with __libc_lock_init before it can be used (or define it
  44    with __libc_lock_define_initialized, below).  Use `extern' for CLASS to
  45    declare a lock defined in another module.  In public structure
  46    definitions you must use a pointer to the lock structure (i.e., NAME
  47    begins with a `*'), because its storage size will not be known outside
  48    of libc.  */
  49 #define __libc_lock_define(CLASS,NAME) \
  50   CLASS __libc_lock_t NAME;
  51
  52 /* Define an initialized lock variable NAME with storage class CLASS.  */
  53 #define _LIBC_LOCK_INITIALIZER MUTEX_INITIALIZER
  54 #define __libc_lock_define_initialized(CLASS,NAME) \
  55   CLASS __libc_lock_t NAME = _LIBC_LOCK_INITIALIZER;
  56
  57 /* Initialize the named lock variable, leaving it in a consistent, unlocked
  58    state.  */
  59 #define __libc_lock_init(NAME) __mutex_init (&(NAME))
  60
  61 /* Finalize the named lock variable, which must be locked.  It cannot be
  62    used again until __libc_lock_init is called again on it.  This must be
  63    called on a lock variable before the containing storage is reused.  */
  64 #define __libc_lock_fini(NAME) __mutex_unlock (&(NAME))
  65 #define __libc_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  66 #define __rtld_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  67
  68
  69 /* Lock the named lock variable.  */
  70 #define __libc_lock_lock(NAME) __mutex_lock (&(NAME))
  71
  72 /* Lock the named lock variable.  */
  73 #define __libc_lock_trylock(NAME) (!__mutex_trylock (&(NAME)))
  74
  75 /* Unlock the named lock variable.  */
  76 #define __libc_lock_unlock(NAME) __mutex_unlock (&(NAME))
  77
  78
  79 #define __libc_lock_define_recursive(CLASS,NAME) \
  80   CLASS __libc_lock_recursive_t NAME;
  81 #define _LIBC_LOCK_RECURSIVE_INITIALIZER { MUTEX_INITIALIZER, 0, 0 }
  82 #define __libc_lock_define_initialized_recursive(CLASS,NAME) \
  83   CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
  84
  85 #define __rtld_lock_define_recursive(CLASS,NAME) \
  86   __libc_lock_define_recursive (CLASS, NAME)
  87 #define _RTLD_LOCK_RECURSIVE_INITIALIZER \
  88   _LIBC_LOCK_RECURSIVE_INITIALIZER
  89 #define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
  90   __libc_lock_define_initialized_recursive (CLASS, NAME)
  91
  92 #define __libc_lock_init_recursive(NAME) \
  93   ({ __libc_lock_recursive_t *const __lock = &(NAME); \
  94      __lock->owner = 0; mutex_init (&__lock->mutex); })
  95
  96 #define __libc_lock_trylock_recursive(NAME)                                   \
  97   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
  98      void *__self = __libc_lock_owner_self ();                                \
  99      __mutex_trylock (&__lock->mutex)                                         \
 100      ? (__lock->owner = __self, __lock->count = 1, 0)                         \
 101      : __lock->owner == __self ? (++__lock->count, 0) : 1; })
 102
 103 #define __libc_lock_lock_recursive(NAME)                                      \
 104   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 105      void *__self = __libc_lock_owner_self ();                                \
 106      if (__mutex_trylock (&__lock->mutex)                                     \
 107          || (__lock->owner != __self                                          \
 108              && (__mutex_lock (&__lock->mutex), 1)))                          \
 109        __lock->owner = __self, __lock->count = 1;                             \
 110      else                                                                     \
 111        ++__lock->count;                                                       \
 112   })
 113 #define __libc_lock_unlock_recursive(NAME)                                    \
 114   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 115      if (--__lock->count == 0)                                                \
 116        {                                                                      \
 117          __lock->owner = 0;                                                   \
 118          __mutex_unlock (&__lock->mutex);                                     \
 119        }                                                                      \
 120   })
 121
 122
 123 #define __rtld_lock_initialize(NAME) \
 124   (void) ((NAME) = (__rtld_lock_recursive_t) _RTLD_LOCK_RECURSIVE_INITIALIZER)
 125 #define __rtld_lock_trylock_recursive(NAME) \
 126   __libc_lock_trylock_recursive (NAME)
 127 #define __rtld_lock_lock_recursive(NAME) \
 128   __libc_lock_lock_recursive(NAME)
 129 #define __rtld_lock_unlock_recursive(NAME) \
 130   __libc_lock_unlock_recursive (NAME)
 131
 132
 133 /* XXX for now */
 134 #define __libc_rwlock_define            __libc_lock_define
 135 #define __libc_rwlock_define_initialized __libc_lock_define_initialized
 136 #define __libc_rwlock_init              __libc_lock_init
 137 #define __libc_rwlock_fini              __libc_lock_fini
 138 #define __libc_rwlock_rdlock            __libc_lock_lock
 139 #define __libc_rwlock_wrlock            __libc_lock_lock
 140 #define __libc_rwlock_tryrdlock         __libc_lock_trylock
 141 #define __libc_rwlock_trywrlock         __libc_lock_trylock
 142 #define __libc_rwlock_unlock            __libc_lock_unlock
 143
 144
 145 /* Start a critical region with a cleanup function */
 146 #define __libc_cleanup_region_start(DOIT, FCT, ARG)                         \
 147 {                                                                           \
 148   typeof (***(FCT)) *__save_FCT = (DOIT) ? (FCT) : 0;                       \
 149   typeof (ARG) __save_ARG = ARG;                                            \
 150   /* close brace is in __libc_cleanup_region_end below. */
 151
 152 /* End a critical region started with __libc_cleanup_region_start. */
 153 #define __libc_cleanup_region_end(DOIT)                                     \
 154   if ((DOIT) && __save_FCT != 0)                                            \
 155     (*__save_FCT)(__save_ARG);                                              \
 156 }
 157
 158 /* Sometimes we have to exit the block in the middle.  */
 159 #define __libc_cleanup_end(DOIT)                                            \
 160   if ((DOIT) && __save_FCT != 0)                                            \
 161     (*__save_FCT)(__save_ARG);                                              \
 162
 163 #define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
 164 #define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
 165
 166 #if (_CTHREADS_ - 0)
 167
 168 /* Use mutexes as once control variables. */
 169
 170 struct __libc_once
 171   {
 172     __libc_lock_t lock;
 173     int done;
 174   };
 175
 176 #define __libc_once_define(CLASS,NAME) \
 177   CLASS struct __libc_once NAME = { MUTEX_INITIALIZER, 0 }
 178
 179 /* Call handler iff the first call.  */
 180 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
 181   do {                                                                        \
 182     __libc_lock_lock (ONCE_CONTROL.lock);                                     \
 183     if (!ONCE_CONTROL.done)                                                   \
 184       (INIT_FUNCTION) ();                                                     \
 185     ONCE_CONTROL.done = 1;                                                    \
 186     __libc_lock_unlock (ONCE_CONTROL.lock);                                   \
 187   } while (0)
 188
 189 /* Get once control variable.  */
 190 #define __libc_once_get(ONCE_CONTROL)   ((ONCE_CONTROL).done != 0)
 191
 192 #ifdef _LIBC
 193 /* We need portable names for some functions.  E.g., when they are
 194    used as argument to __libc_cleanup_region_start.  */
 195 #define __libc_mutex_unlock __mutex_unlock
 196 #endif
 197
 198 /* Type for key of thread specific data.  */
 199 typedef cthread_key_t __libc_key_t;
 200
 201 #define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
 202 #define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
 203 void *__libc_getspecific (__libc_key_t key);
 204
 205 #endif /* _CTHREADS_ */
 206
 207 /* Hide the definitions which are only supposed to be used inside libc in
 208    a separate file.  This file is not present in the installation!  */
 209 #ifdef _LIBC
 210 # include <libc-lockP.h>
 211 #endif
 212
 213 #endif  /* libc-lock.h */