sysdeps/mach/hurd/bits/libc-lock.h

   1 /* libc-internal interface for mutex locks.  Hurd version using Mach cthreads.
   2    Copyright (C) 1996,97,98,2000,01, 2002, 2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _BITS_LIBC_LOCK_H
  21 #define _BITS_LIBC_LOCK_H 1
  22
  23 #if (_LIBC - 0) || (_CTHREADS_ - 0)
  24 #include <cthreads.h>
  25 #include <hurd/threadvar.h>
  26
  27 typedef struct mutex __libc_lock_t;
  28 typedef struct
  29 {
  30   struct mutex mutex;
  31   void *owner;
  32   int count;
  33 } __libc_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_define_initialized(CLASS,NAME) \
  54   CLASS __libc_lock_t NAME = MUTEX_INITIALIZER;
  55
  56 /* Initialize the named lock variable, leaving it in a consistent, unlocked
  57    state.  */
  58 #define __libc_lock_init(NAME) __mutex_init (&(NAME))
  59
  60 /* Finalize the named lock variable, which must be locked.  It cannot be
  61    used again until __libc_lock_init is called again on it.  This must be
  62    called on a lock variable before the containing storage is reused.  */
  63 #define __libc_lock_fini(NAME) __mutex_unlock (&(NAME))
  64 #define __libc_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  65 #define __rtld_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  66
  67
  68 /* Lock the named lock variable.  */
  69 #define __libc_lock_lock(NAME) __mutex_lock (&(NAME))
  70
  71 /* Lock the named lock variable.  */
  72 #define __libc_lock_trylock(NAME) (!__mutex_trylock (&(NAME)))
  73
  74 /* Unlock the named lock variable.  */
  75 #define __libc_lock_unlock(NAME) __mutex_unlock (&(NAME))
  76
  77
  78 #define __libc_lock_define_recursive(CLASS,NAME) \
  79   CLASS __libc_lock_recursive_t NAME;
  80 #define _LIBC_LOCK_RECURSIVE_INITIALIZER { MUTEX_INITIALIZER, 0, 0 }
  81 #define __libc_lock_define_initialized_recursive(CLASS,NAME) \
  82   CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
  83
  84 #define __rtld_lock_define_recursive(CLASS,NAME) \
  85   __libc_lock_define_recursive (CLASS, NAME)
  86 #define _RTLD_LOCK_RECURSIVE_INITIALIZER \
  87   _LIBC_LOCK_RECURSIVE_INITIALIZER
  88 #define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
  89   __libc_lock_define_initialized_recursive (CLASS, NAME)
  90
  91 #define __libc_lock_init_recursive(NAME) \
  92   ({ __libc_lock_recursive_t *const __lock = &(NAME); \
  93      __lock->owner = 0; mutex_init (&__lock->mutex); })
  94
  95 #define __libc_lock_trylock_recursive(NAME)                                   \
  96   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
  97      void *__self = __libc_lock_owner_self ();                                \
  98      __mutex_trylock (&__lock->mutex)                                         \
  99      ? (__lock->owner = __self, __lock->count = 1, 0)                         \
 100      : __lock->owner == __self ? (++__lock->count, 0) : 1; })
 101
 102 #define __libc_lock_lock_recursive(NAME)                                      \
 103   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 104      void *__self = __libc_lock_owner_self ();                                \
 105      if (__mutex_trylock (&__lock->mutex)                                     \
 106          || (__lock->owner != __self                                          \
 107              && (__mutex_lock (&__lock->mutex), 1)))                          \
 108        __lock->owner = __self, __lock->count = 1;                             \
 109      else                                                                     \
 110        ++__lock->count;                                                       \
 111   })
 112 #define __libc_lock_unlock_recursive(NAME)                                    \
 113   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 114      if (--__lock->count == 0)                                                \
 115        {                                                                      \
 116          __lock->owner = 0;                                                   \
 117          __mutex_unlock (&__lock->mutex);                                     \
 118        }                                                                      \
 119   })
 120
 121
 122 #define __rtld_lock_init_recursive(NAME) \
 123   __libc_lock_init_recursive (NAME)
 124 #define __rtld_lock_trylock_recursive(NAME) \
 125   __libc_lock_trylock_recursive (NAME)
 126 #define __rtld_lock_lock_recursive(NAME) \
 127   __libc_lock_lock_recursive(NAME)
 128 #define __rtld_lock_unlock_recursive(NAME) \
 129   __libc_lock_unlock_recursive (NAME)
 130
 131
 132 /* XXX for now */
 133 #define __libc_rwlock_define            __libc_lock_define
 134 #define __libc_rwlock_define_initialized __libc_lock_define_initialized
 135 #define __libc_rwlock_init              __libc_lock_init
 136 #define __libc_rwlock_fini              __libc_lock_fini
 137 #define __libc_rwlock_rdlock            __libc_lock_lock
 138 #define __libc_rwlock_wrlock            __libc_lock_lock
 139 #define __libc_rwlock_tryrdlock         __libc_lock_trylock
 140 #define __libc_rwlock_trywrlock         __libc_lock_trylock
 141 #define __libc_rwlock_unlock            __libc_lock_unlock
 142
 143
 144 /* Start a critical region with a cleanup function */
 145 #define __libc_cleanup_region_start(DOIT, FCT, ARG)                         \
 146 {                                                                           \
 147   typeof (***(FCT)) *__save_FCT = (DOIT) ? (FCT) : 0;                       \
 148   typeof (ARG) __save_ARG = ARG;                                            \
 149   /* close brace is in __libc_cleanup_region_end below. */
 150
 151 /* End a critical region started with __libc_cleanup_region_start. */
 152 #define __libc_cleanup_region_end(DOIT)                                     \
 153   if ((DOIT) && __save_FCT != 0)                                            \
 154     (*__save_FCT)(__save_ARG);                                              \
 155 }
 156
 157 /* Sometimes we have to exit the block in the middle.  */
 158 #define __libc_cleanup_end(DOIT)                                            \
 159   if ((DOIT) && __save_FCT != 0)                                            \
 160     (*__save_FCT)(__save_ARG);                                              \
 161
 162 #define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
 163 #define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
 164
 165 #if (_CTHREADS_ - 0)
 166
 167 /* Use mutexes as once control variables. */
 168
 169 struct __libc_once
 170   {
 171     __libc_lock_t lock;
 172     int done;
 173   };
 174
 175 #define __libc_once_define(CLASS,NAME) \
 176   CLASS struct __libc_once NAME = { MUTEX_INITIALIZER, 0 }
 177
 178 /* Call handler iff the first call.  */
 179 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
 180   do {                                                                        \
 181     __libc_lock_lock (ONCE_CONTROL.lock);                                     \
 182     if (!ONCE_CONTROL.done)                                                   \
 183       (INIT_FUNCTION) ();                                                     \
 184     ONCE_CONTROL.done = 1;                                                    \
 185     __libc_lock_unlock (ONCE_CONTROL.lock);                                   \
 186   } while (0)
 187
 188 #ifdef _LIBC
 189 /* We need portable names for some functions.  E.g., when they are
 190    used as argument to __libc_cleanup_region_start.  */
 191 #define __libc_mutex_unlock __mutex_unlock
 192 #endif
 193
 194 /* Type for key of thread specific data.  */
 195 typedef cthread_key_t __libc_key_t;
 196
 197 #define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
 198 #define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
 199 void *__libc_getspecific (__libc_key_t key);
 200
 201 #endif /* _CTHREADS_ */
 202
 203 #endif  /* bits/libc-lock.h */