sysdeps/mach/libc-lock.h

   1 /* libc-internal interface for mutex locks.  Mach cthreads version.
   2    Copyright (C) 1996-2023 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    <https://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 typedef unsigned int __libc_lock_t;
  28 typedef struct
  29 {
  30   __libc_lock_t lock;
  31   int cnt;
  32   void *owner;
  33 } __libc_lock_recursive_t;
  34
  35 typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
  36
  37 #define __libc_lock_owner_self()   \
  38   (__LIBC_NO_TLS () ? (void *) 1 : 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 LLL_LOCK_INITIALIZER
  57 #define __libc_lock_define_initialized(CLASS,NAME) \
  58   CLASS __libc_lock_t NAME = LLL_LOCK_INITIALIZER;
  59
  60 /* Initialize the named lock variable, leaving it in a consistent, unlocked
  61    state.  */
  62 #define __libc_lock_init(NAME) (NAME) = LLL_LOCK_INITIALIZER
  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             __libc_lock_unlock
  68 #define __libc_lock_fini_recursive   __libc_lock_unlock_recursive
  69 #define __rtld_lock_fini_recursive   __rtld_lock_unlock_recursive
  70
  71 /* Lock the named lock variable.  */
  72 #define __libc_lock_lock(NAME)   \
  73   ({ lll_lock ((NAME), LLL_PRIVATE); 0; })
  74
  75 /* Lock the named lock variable.  */
  76 #define __libc_lock_trylock(NAME) lll_trylock (NAME)
  77
  78 /* Unlock the named lock variable.  */
  79 #define __libc_lock_unlock(NAME)   \
  80   ({ lll_unlock ((NAME), LLL_PRIVATE); 0; })
  81
  82 #define __libc_lock_define_recursive(CLASS,NAME) \
  83   CLASS __libc_lock_recursive_t NAME;
  84
  85 #define _LIBC_LOCK_RECURSIVE_INITIALIZER { LLL_LOCK_INITIALIZER, 0, 0 }
  86
  87 #define __libc_lock_define_initialized_recursive(CLASS,NAME) \
  88   CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
  89
  90 #define __rtld_lock_define_recursive(CLASS,NAME) \
  91   __libc_lock_define_recursive (CLASS, NAME)
  92 #define _RTLD_LOCK_RECURSIVE_INITIALIZER \
  93   _LIBC_LOCK_RECURSIVE_INITIALIZER
  94 #define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
  95   __libc_lock_define_initialized_recursive (CLASS, NAME)
  96
  97 #define __libc_lock_init_recursive(NAME)   \
  98   ({   \
  99      (NAME) = (__libc_lock_recursive_t)_LIBC_LOCK_RECURSIVE_INITIALIZER;   \
 100      0;   \
 101   })
 102
 103 #define __libc_lock_trylock_recursive(NAME)   \
 104   ({   \
 105      __libc_lock_recursive_t *const __lock = &(NAME);   \
 106      void *__self = __libc_lock_owner_self ();   \
 107      int __r = 0;   \
 108      if (__self == __lock->owner)   \
 109        ++__lock->cnt;   \
 110      else if ((__r = lll_trylock (__lock->lock)) == 0)   \
 111        __lock->owner = __self, __lock->cnt = 1;   \
 112      __r;   \
 113    })
 114
 115 #define __libc_lock_lock_recursive(NAME)   \
 116   ({   \
 117      __libc_lock_recursive_t *const __lock = &(NAME);   \
 118      void *__self = __libc_lock_owner_self ();   \
 119      if (__self != __lock->owner)   \
 120        {   \
 121          lll_lock (__lock->lock, 0);   \
 122          __lock->owner = __self;   \
 123        }   \
 124      ++__lock->cnt;   \
 125      (void)0;   \
 126    })
 127
 128 #define __libc_lock_unlock_recursive(NAME)   \
 129   ({   \
 130      __libc_lock_recursive_t *const __lock = &(NAME);   \
 131      if (--__lock->cnt == 0)   \
 132        {   \
 133          __lock->owner = 0;   \
 134          lll_unlock (__lock->lock, 0);   \
 135        }   \
 136    })
 137
 138
 139 #define __rtld_lock_initialize(NAME) \
 140   (void) ((NAME) = (__rtld_lock_recursive_t) _RTLD_LOCK_RECURSIVE_INITIALIZER)
 141 #define __rtld_lock_trylock_recursive(NAME) \
 142   __libc_lock_trylock_recursive (NAME)
 143 #define __rtld_lock_lock_recursive(NAME) \
 144   __libc_lock_lock_recursive(NAME)
 145 #define __rtld_lock_unlock_recursive(NAME) \
 146   __libc_lock_unlock_recursive (NAME)
 147
 148 /* XXX for now */
 149 #define __libc_rwlock_define            __libc_lock_define
 150 #define __libc_rwlock_define_initialized __libc_lock_define_initialized
 151 #define __libc_rwlock_init              __libc_lock_init
 152 #define __libc_rwlock_fini              __libc_lock_fini
 153 #define __libc_rwlock_rdlock            __libc_lock_lock
 154 #define __libc_rwlock_wrlock            __libc_lock_lock
 155 #define __libc_rwlock_tryrdlock         __libc_lock_trylock
 156 #define __libc_rwlock_trywrlock         __libc_lock_trylock
 157 #define __libc_rwlock_unlock            __libc_lock_unlock
 158
 159 struct __libc_cleanup_frame
 160 {
 161   void (*__fct) (void *);
 162   void *__argp;
 163   int __doit;
 164 };
 165
 166 __extern_inline void
 167 __libc_cleanup_fct (struct __libc_cleanup_frame *framep)
 168 {
 169   if (framep->__doit)
 170     framep->__fct (framep->__argp);
 171 }
 172
 173 /* Start a critical region with a cleanup function */
 174 #define __libc_cleanup_region_start(DOIT, FCT, ARG)   \
 175   do   \
 176     {   \
 177       struct __libc_cleanup_frame __cleanup   \
 178         __attribute__ ((__cleanup__ (__libc_cleanup_fct))) =   \
 179         { .__fct = (FCT), .__argp = (ARG), .__doit = (DOIT) };
 180
 181 /* This one closes the brace above.  */
 182 #define __libc_cleanup_region_end(DOIT)   \
 183       __cleanup.__doit = (DOIT);   \
 184     }   \
 185   while (0)
 186
 187 #define __libc_cleanup_end(DOIT)   __cleanup.__doit = (DOIT);
 188
 189 #define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
 190 #define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
 191
 192 /* Use mutexes as once control variables.  */
 193
 194 struct __libc_once
 195   {
 196     __libc_lock_t lock;
 197     int done;
 198   };
 199
 200 #define __libc_once_define(CLASS,NAME) \
 201   CLASS struct __libc_once NAME = { _LIBC_LOCK_INITIALIZER, 0 }
 202
 203 /* Call handler iff the first call.  */
 204 #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
 205   do {                                                                        \
 206     __libc_lock_lock (ONCE_CONTROL.lock);                                     \
 207     if (!ONCE_CONTROL.done)                                                   \
 208       (INIT_FUNCTION) ();                                                     \
 209     ONCE_CONTROL.done = 1;                                                    \
 210     __libc_lock_unlock (ONCE_CONTROL.lock);                                   \
 211   } while (0)
 212
 213 /* Get once control variable.  */
 214 #define __libc_once_get(ONCE_CONTROL)   ((ONCE_CONTROL).done != 0)
 215
 216 #ifdef _LIBC
 217 /* We need portable names for some functions.  E.g., when they are
 218    used as argument to __libc_cleanup_region_start.  */
 219 #define __libc_mutex_unlock __libc_lock_unlock
 220
 221 /* Hide the definitions which are only supposed to be used inside libc in
 222    a separate file.  This file is not present in the installation!  */
 223 # include <libc-lockP.h>
 224 #endif
 225
 226 #endif  /* libc-lock.h */