sysdeps/mach/libc-lock.h

   1 /* libc-internal interface for mutex locks.  Mach cthreads version.
   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 #ifdef _LIBC
  23
  24 #include <tls.h>
  25 #include <lowlevellock.h>
  26
  27 /* The locking here is very inexpensive, even for inlining.  */
  28 #define _IO_lock_inexpensive   1
  29
  30 typedef unsigned int __libc_lock_t;
  31 typedef struct
  32 {
  33   __libc_lock_t lock;
  34   int cnt;
  35   void *owner;
  36 } __libc_lock_recursive_t;
  37
  38 typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
  39
  40 extern char __libc_lock_self0[0];
  41 #define __libc_lock_owner_self()   \
  42   (__LIBC_NO_TLS () ? (void *)&__libc_lock_self0 : THREAD_SELF)
  43
  44 #else
  45 typedef struct __libc_lock_opaque__ __libc_lock_t;
  46 typedef struct __libc_lock_recursive_opaque__ __libc_lock_recursive_t;
  47 #endif
  48
  49 /* Define a lock variable NAME with storage class CLASS.  The lock must be
  50    initialized with __libc_lock_init before it can be used (or define it
  51    with __libc_lock_define_initialized, below).  Use `extern' for CLASS to
  52    declare a lock defined in another module.  In public structure
  53    definitions you must use a pointer to the lock structure (i.e., NAME
  54    begins with a `*'), because its storage size will not be known outside
  55    of libc.  */
  56 #define __libc_lock_define(CLASS,NAME) \
  57   CLASS __libc_lock_t NAME;
  58
  59 /* Define an initialized lock variable NAME with storage class CLASS.  */
  60 #define _LIBC_LOCK_INITIALIZER LLL_INITIALIZER
  61 #define __libc_lock_define_initialized(CLASS,NAME) \
  62   CLASS __libc_lock_t NAME = LLL_INITIALIZER;
  63
  64 /* Initialize the named lock variable, leaving it in a consistent, unlocked
  65    state.  */
  66 #define __libc_lock_init(NAME) (NAME) = LLL_INITIALIZER
  67
  68 /* Finalize the named lock variable, which must be locked.  It cannot be
  69    used again until __libc_lock_init is called again on it.  This must be
  70    called on a lock variable before the containing storage is reused.  */
  71 #define __libc_lock_fini             __libc_lock_unlock
  72 #define __libc_lock_fini_recursive   __libc_lock_unlock_recursive
  73 #define __rtld_lock_fini_recursive   __rtld_lock_unlock_recursive
  74
  75 /* Lock the named lock variable.  */
  76 #define __libc_lock_lock(NAME)   \
  77   ({ lll_lock (&(NAME), 0); 0; })
  78
  79 /* Lock the named lock variable.  */
  80 #define __libc_lock_trylock(NAME) lll_trylock (&(NAME))
  81
  82 /* Unlock the named lock variable.  */
  83 #define __libc_lock_unlock(NAME)   \
  84   ({ lll_unlock (&(NAME), 0); 0; })
  85
  86 #define __libc_lock_define_recursive(CLASS,NAME) \
  87   CLASS __libc_lock_recursive_t NAME;
  88
  89 #define _LIBC_LOCK_RECURSIVE_INITIALIZER { LLL_INITIALIZER, 0, 0 }
  90
  91 #define __libc_lock_define_initialized_recursive(CLASS,NAME) \
  92   CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
  93
  94 #define __rtld_lock_define_recursive(CLASS,NAME) \
  95   __libc_lock_define_recursive (CLASS, NAME)
  96 #define _RTLD_LOCK_RECURSIVE_INITIALIZER \
  97   _LIBC_LOCK_RECURSIVE_INITIALIZER
  98 #define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
  99   __libc_lock_define_initialized_recursive (CLASS, NAME)
 100
 101 #define __libc_lock_init_recursive(NAME)   \
 102   ({   \
 103      (NAME) = (__libc_lock_recursive_t)_LIBC_LOCK_RECURSIVE_INITIALIZER;   \
 104      0;   \
 105   })
 106
 107 #define __libc_lock_trylock_recursive(NAME)   \
 108   ({   \
 109      __libc_lock_recursive_t *const __lock = &(NAME);   \
 110      void *__self = __libc_lock_owner_self ();   \
 111      int __r = 0;   \
 112      if (__self == __lock->owner)   \
 113        ++__lock->cnt;   \
 114      else if ((__r = lll_trylock (&__lock->lock)) == 0)   \
 115        __lock->owner = __self, __lock->cnt = 1;   \
 116      __r;   \
 117    })
 118
 119 #define __libc_lock_lock_recursive(NAME)   \
 120   ({   \
 121      __libc_lock_recursive_t *const __lock = &(NAME);   \
 122      void *__self = __libc_lock_owner_self ();   \
 123      if (__self != __lock->owner)   \
 124        {   \
 125          lll_lock (&__lock->lock, 0);   \
 126          __lock->owner = __self;   \
 127        }   \
 128      ++__lock->cnt;   \
 129      (void)0;   \
 130    })
 131
 132 #define __libc_lock_unlock_recursive(NAME)   \
 133   ({   \
 134      __libc_lock_recursive_t *const __lock = &(NAME);   \
 135      if (--__lock->cnt == 0)   \
 136        {   \
 137          __lock->owner = 0;   \
 138          lll_unlock (&__lock->lock, 0);   \
 139        }   \
 140    })
 141
 142
 143 #define __rtld_lock_initialize(NAME) \
 144   (void) ((NAME) = (__rtld_lock_recursive_t) _RTLD_LOCK_RECURSIVE_INITIALIZER)
 145 #define __rtld_lock_trylock_recursive(NAME) \
 146   __libc_lock_trylock_recursive (NAME)
 147 #define __rtld_lock_lock_recursive(NAME) \
 148   __libc_lock_lock_recursive(NAME)
 149 #define __rtld_lock_unlock_recursive(NAME) \
 150   __libc_lock_unlock_recursive (NAME)
 151
 152 /* XXX for now */
 153 #define __libc_rwlock_define            __libc_lock_define
 154 #define __libc_rwlock_define_initialized __libc_lock_define_initialized
 155 #define __libc_rwlock_init              __libc_lock_init
 156 #define __libc_rwlock_fini              __libc_lock_fini
 157 #define __libc_rwlock_rdlock            __libc_lock_lock
 158 #define __libc_rwlock_wrlock            __libc_lock_lock
 159 #define __libc_rwlock_tryrdlock         __libc_lock_trylock
 160 #define __libc_rwlock_trywrlock         __libc_lock_trylock
 161 #define __libc_rwlock_unlock            __libc_lock_unlock
 162
 163 struct __libc_cleanup_frame
 164 {
 165   void (*__fct) (void *);
 166   void *__argp;
 167   int __doit;
 168 };
 169
 170 __extern_inline void
 171 __libc_cleanup_fct (struct __libc_cleanup_frame *framep)
 172 {
 173   if (framep->__doit)
 174     framep->__fct (framep->__argp);
 175 }
 176
 177 /* Start a critical region with a cleanup function */
 178 #define __libc_cleanup_region_start(DOIT, FCT, ARG)   \
 179   do   \
 180     {   \
 181       struct __libc_cleanup_frame __cleanup   \
 182         __attribute__ ((__cleanup__ (__libc_cleanup_fct))) =   \
 183         { .__fct = (FCT), .__argp = (ARG), .__doit = (DOIT) };
 184
 185 /* This one closes the brace above.  */
 186 #define __libc_cleanup_region_end(DOIT)   \
 187       __cleanup.__doit = (DOIT);   \
 188     }   \
 189   while (0)
 190
 191 #define __libc_cleanup_end(DOIT)   __cleanup.__doit = (DOIT);
 192
 193 #define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
 194 #define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
 195
 196 /* Use mutexes as once control variables.  */
 197
 198 struct __libc_once
 199   {
 200     __libc_lock_t lock;
 201     int done;
 202   };
 203
 204 #define __libc_once_define(CLASS,NAME) \
 205   CLASS struct __libc_once NAME = { _LIBC_LOCK_INITIALIZER, 0 }
 206
 207 /* Call handler iff the first call.  */
 208 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
 209   do {                                                                        \
 210     __libc_lock_lock (ONCE_CONTROL.lock);                                     \
 211     if (!ONCE_CONTROL.done)                                                   \
 212       (INIT_FUNCTION) ();                                                     \
 213     ONCE_CONTROL.done = 1;                                                    \
 214     __libc_lock_unlock (ONCE_CONTROL.lock);                                   \
 215   } while (0)
 216
 217 /* Get once control variable.  */
 218 #define __libc_once_get(ONCE_CONTROL)   ((ONCE_CONTROL).done != 0)
 219
 220 #ifdef _LIBC
 221 /* We need portable names for some functions.  E.g., when they are
 222    used as argument to __libc_cleanup_region_start.  */
 223 #define __libc_mutex_unlock __libc_lock_unlock
 224
 225 /* Hide the definitions which are only supposed to be used inside libc in
 226    a separate file.  This file is not present in the installation!  */
 227 # include <libc-lockP.h>
 228 #endif
 229
 230 #endif  /* libc-lock.h */