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