sysdeps/mach/hurd/libc-lock.h

   1 /* libc-internal interface for mutex locks.  Hurd version using Mach cthreads.
   2    Copyright (C) 1996-2018 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
  25 /* The locking here is very inexpensive, even for inlining.  */
  26 #define _IO_lock_inexpensive  1
  27
  28 typedef struct mutex __libc_lock_t;
  29 typedef struct
  30 {
  31   struct mutex mutex;
  32   void *owner;
  33   int count;
  34 } __libc_lock_recursive_t;
  35 typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
  36
  37 extern char __libc_lock_self0[0];
  38 #define __libc_lock_owner_self() (__LIBC_NO_TLS() ? &__libc_lock_self0 : THREAD_SELF)
  39
  40 #else
  41 typedef struct __libc_lock_opaque__ __libc_lock_t;
  42 typedef struct __libc_lock_recursive_opaque__ __libc_lock_recursive_t;
  43 #endif
  44
  45 /* Define a lock variable NAME with storage class CLASS.  The lock must be
  46    initialized with __libc_lock_init before it can be used (or define it
  47    with __libc_lock_define_initialized, below).  Use `extern' for CLASS to
  48    declare a lock defined in another module.  In public structure
  49    definitions you must use a pointer to the lock structure (i.e., NAME
  50    begins with a `*'), because its storage size will not be known outside
  51    of libc.  */
  52 #define __libc_lock_define(CLASS,NAME) \
  53   CLASS __libc_lock_t NAME;
  54
  55 /* Define an initialized lock variable NAME with storage class CLASS.  */
  56 #define _LIBC_LOCK_INITIALIZER MUTEX_INITIALIZER
  57 #define __libc_lock_define_initialized(CLASS,NAME) \
  58   CLASS __libc_lock_t NAME = _LIBC_LOCK_INITIALIZER;
  59
  60 /* Initialize the named lock variable, leaving it in a consistent, unlocked
  61    state.  */
  62 #define __libc_lock_init(NAME) __mutex_init (&(NAME))
  63
  64 /* Finalize the named lock variable, which must be locked.  It cannot be
  65    used again until __libc_lock_init is called again on it.  This must be
  66    called on a lock variable before the containing storage is reused.  */
  67 #define __libc_lock_fini(NAME) __mutex_unlock (&(NAME))
  68 #define __libc_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  69 #define __rtld_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  70
  71
  72 /* Lock the named lock variable.  */
  73 #define __libc_lock_lock(NAME) __mutex_lock (&(NAME))
  74
  75 /* Lock the named lock variable.  */
  76 #define __libc_lock_trylock(NAME) (!__mutex_trylock (&(NAME)))
  77
  78 /* Unlock the named lock variable.  */
  79 #define __libc_lock_unlock(NAME) __mutex_unlock (&(NAME))
  80
  81
  82 #define __libc_lock_define_recursive(CLASS,NAME) \
  83   CLASS __libc_lock_recursive_t NAME;
  84 #define _LIBC_LOCK_RECURSIVE_INITIALIZER { MUTEX_INITIALIZER, 0, 0 }
  85 #define __libc_lock_define_initialized_recursive(CLASS,NAME) \
  86   CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
  87
  88 #define __rtld_lock_define_recursive(CLASS,NAME) \
  89   __libc_lock_define_recursive (CLASS, NAME)
  90 #define _RTLD_LOCK_RECURSIVE_INITIALIZER \
  91   _LIBC_LOCK_RECURSIVE_INITIALIZER
  92 #define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
  93   __libc_lock_define_initialized_recursive (CLASS, NAME)
  94
  95 #define __libc_lock_init_recursive(NAME) \
  96   ({ __libc_lock_recursive_t *const __lock = &(NAME); \
  97      __lock->owner = 0; mutex_init (&__lock->mutex); })
  98
  99 #define __libc_lock_trylock_recursive(NAME)                                   \
 100   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 101      void *__self = __libc_lock_owner_self ();                                \
 102      __mutex_trylock (&__lock->mutex)                                         \
 103      ? (__lock->owner = __self, __lock->count = 1, 0)                         \
 104      : __lock->owner == __self ? (++__lock->count, 0) : 1; })
 105
 106 #define __libc_lock_lock_recursive(NAME)                                      \
 107   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 108      void *__self = __libc_lock_owner_self ();                                \
 109      if (__mutex_trylock (&__lock->mutex)                                     \
 110          || (__lock->owner != __self                                          \
 111              && (__mutex_lock (&__lock->mutex), 1)))                          \
 112        __lock->owner = __self, __lock->count = 1;                             \
 113      else                                                                     \
 114        ++__lock->count;                                                       \
 115   })
 116 #define __libc_lock_unlock_recursive(NAME)                                    \
 117   ({ __libc_lock_recursive_t *const __lock = &(NAME);                         \
 118      if (--__lock->count == 0)                                                \
 119        {                                                                      \
 120          __lock->owner = 0;                                                   \
 121          __mutex_unlock (&__lock->mutex);                                     \
 122        }                                                                      \
 123   })
 124
 125
 126 #define __rtld_lock_initialize(NAME) \
 127   (void) ((NAME) = (__rtld_lock_recursive_t) _RTLD_LOCK_RECURSIVE_INITIALIZER)
 128 #define __rtld_lock_trylock_recursive(NAME) \
 129   __libc_lock_trylock_recursive (NAME)
 130 #define __rtld_lock_lock_recursive(NAME) \
 131   __libc_lock_lock_recursive(NAME)
 132 #define __rtld_lock_unlock_recursive(NAME) \
 133   __libc_lock_unlock_recursive (NAME)
 134
 135
 136 /* XXX for now */
 137 #define __libc_rwlock_define            __libc_lock_define
 138 #define __libc_rwlock_define_initialized __libc_lock_define_initialized
 139 #define __libc_rwlock_init              __libc_lock_init
 140 #define __libc_rwlock_fini              __libc_lock_fini
 141 #define __libc_rwlock_rdlock            __libc_lock_lock
 142 #define __libc_rwlock_wrlock            __libc_lock_lock
 143 #define __libc_rwlock_tryrdlock         __libc_lock_trylock
 144 #define __libc_rwlock_trywrlock         __libc_lock_trylock
 145 #define __libc_rwlock_unlock            __libc_lock_unlock
 146
 147
 148 /* Start a critical region with a cleanup function */
 149 #define __libc_cleanup_region_start(DOIT, FCT, ARG)                         \
 150 {                                                                           \
 151   typeof (***(FCT)) *__save_FCT = (DOIT) ? (FCT) : 0;                       \
 152   typeof (ARG) __save_ARG = ARG;                                            \
 153   /* close brace is in __libc_cleanup_region_end below. */
 154
 155 /* End a critical region started with __libc_cleanup_region_start. */
 156 #define __libc_cleanup_region_end(DOIT)                                     \
 157   if ((DOIT) && __save_FCT != 0)                                            \
 158     (*__save_FCT)(__save_ARG);                                              \
 159 }
 160
 161 /* Sometimes we have to exit the block in the middle.  */
 162 #define __libc_cleanup_end(DOIT)                                            \
 163   if ((DOIT) && __save_FCT != 0)                                            \
 164     (*__save_FCT)(__save_ARG);                                              \
 165
 166 #define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
 167 #define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
 168
 169 #if (_CTHREADS_ - 0)
 170
 171 /* Use mutexes as once control variables. */
 172
 173 struct __libc_once
 174   {
 175     __libc_lock_t lock;
 176     int done;
 177   };
 178
 179 #define __libc_once_define(CLASS,NAME) \
 180   CLASS struct __libc_once NAME = { MUTEX_INITIALIZER, 0 }
 181
 182 /* Call handler iff the first call.  */
 183 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
 184   do {                                                                        \
 185     __libc_lock_lock (ONCE_CONTROL.lock);                                     \
 186     if (!ONCE_CONTROL.done)                                                   \
 187       (INIT_FUNCTION) ();                                                     \
 188     ONCE_CONTROL.done = 1;                                                    \
 189     __libc_lock_unlock (ONCE_CONTROL.lock);                                   \
 190   } while (0)
 191
 192 /* Get once control variable.  */
 193 #define __libc_once_get(ONCE_CONTROL)   ((ONCE_CONTROL).done != 0)
 194
 195 #ifdef _LIBC
 196 /* We need portable names for some functions.  E.g., when they are
 197    used as argument to __libc_cleanup_region_start.  */
 198 #define __libc_mutex_unlock __mutex_unlock
 199 #endif
 200
 201 /* Type for key of thread specific data.  */
 202 typedef cthread_key_t __libc_key_t;
 203
 204 #define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
 205 #define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
 206 void *__libc_getspecific (__libc_key_t key);
 207
 208 #endif /* _CTHREADS_ */
 209
 210 /* Hide the definitions which are only supposed to be used inside libc in
 211    a separate file.  This file is not present in the installation!  */
 212 #ifdef _LIBC
 213 # include <libc-lockP.h>
 214 #endif
 215
 216 #endif  /* libc-lock.h */