text: /* libc-internal interface for mutex locks.  Hurd version using Mach cthreads.
     Copyright (C) 1996-2012 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <http://www.gnu.org/licenses/>.  */
  
  #ifndef _BITS_LIBC_LOCK_H
  #define _BITS_LIBC_LOCK_H 1
  
  #if (_LIBC - 0) || (_CTHREADS_ - 0)
  #include <cthreads.h>
  #include <hurd/threadvar.h>
  
  typedef struct mutex __libc_lock_t;
  typedef struct
  {
    struct mutex mutex;
    void *owner;
    int count;
  } __libc_lock_recursive_t;
  typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
  
  #define __libc_lock_owner_self() ((void *) __hurd_threadvar_location (0))
  
  #else
  typedef struct __libc_lock_opaque__ __libc_lock_t;
  typedef struct __libc_lock_recursive_opaque__ __libc_lock_recursive_t;
  #endif
  
  /* Define a lock variable NAME with storage class CLASS.  The lock must be
     initialized with __libc_lock_init before it can be used (or define it
     with __libc_lock_define_initialized, below).  Use `extern' for CLASS to
     declare a lock defined in another module.  In public structure
     definitions you must use a pointer to the lock structure (i.e., NAME
     begins with a `*'), because its storage size will not be known outside
     of libc.  */
  #define __libc_lock_define(CLASS,NAME) \
    CLASS __libc_lock_t NAME;
  
  /* Define an initialized lock variable NAME with storage class CLASS.  */
  #define __libc_lock_define_initialized(CLASS,NAME) \
    CLASS __libc_lock_t NAME = MUTEX_INITIALIZER;
  
  /* Initialize the named lock variable, leaving it in a consistent, unlocked
     state.  */
  #define __libc_lock_init(NAME) __mutex_init (&(NAME))
  
  /* Finalize the named lock variable, which must be locked.  It cannot be
     used again until __libc_lock_init is called again on it.  This must be
     called on a lock variable before the containing storage is reused.  */
  #define __libc_lock_fini(NAME) __mutex_unlock (&(NAME))
  #define __libc_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  #define __rtld_lock_fini_recursive(NAME) __mutex_unlock (&(NAME).mutex)
  
  
  /* Lock the named lock variable.  */
  #define __libc_lock_lock(NAME) __mutex_lock (&(NAME))
  
  /* Lock the named lock variable.  */
  #define __libc_lock_trylock(NAME) (!__mutex_trylock (&(NAME)))
  
  /* Unlock the named lock variable.  */
  #define __libc_lock_unlock(NAME) __mutex_unlock (&(NAME))
  
  
  #define __libc_lock_define_recursive(CLASS,NAME) \
    CLASS __libc_lock_recursive_t NAME;
  #define _LIBC_LOCK_RECURSIVE_INITIALIZER { MUTEX_INITIALIZER, 0, 0 }
  #define __libc_lock_define_initialized_recursive(CLASS,NAME) \
    CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
  
  #define __rtld_lock_define_recursive(CLASS,NAME) \
    __libc_lock_define_recursive (CLASS, NAME)
  #define _RTLD_LOCK_RECURSIVE_INITIALIZER \
    _LIBC_LOCK_RECURSIVE_INITIALIZER
  #define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
    __libc_lock_define_initialized_recursive (CLASS, NAME)
  
  #define __libc_lock_init_recursive(NAME) \
    ({ __libc_lock_recursive_t *const __lock = &(NAME); \
       __lock->owner = 0; mutex_init (&__lock->mutex); })
  
  #define __libc_lock_trylock_recursive(NAME)				      \
    ({ __libc_lock_recursive_t *const __lock = &(NAME);			      \
       void *__self = __libc_lock_owner_self ();				      \
       __mutex_trylock (&__lock->mutex)					      \
       ? (__lock->owner = __self, __lock->count = 1, 0)			      \
       : __lock->owner == __self ? (++__lock->count, 0) : 1; })
  
  #define __libc_lock_lock_recursive(NAME)				      \
    ({ __libc_lock_recursive_t *const __lock = &(NAME);			      \
       void *__self = __libc_lock_owner_self ();				      \
       if (__mutex_trylock (&__lock->mutex)				      \
  	 || (__lock->owner != __self					      \
  	     && (__mutex_lock (&__lock->mutex), 1)))			      \
         __lock->owner = __self, __lock->count = 1;			      \
       else								      \
         ++__lock->count;							      \
    })
  #define __libc_lock_unlock_recursive(NAME)				      \
    ({ __libc_lock_recursive_t *const __lock = &(NAME);			      \
       if (--__lock->count == 0)						      \
         {								      \
  	 __lock->owner = 0;						      \
  	 __mutex_unlock (&__lock->mutex);				      \
         }								      \
    })
  
  
  #define __rtld_lock_init_recursive(NAME) \
    __libc_lock_init_recursive (NAME)
  #define __rtld_lock_initialize(NAME) \
    (void) ((NAME) = (__rtld_lock_recursive_t) _RTLD_LOCK_RECURSIVE_INITIALIZER)
  #define __rtld_lock_trylock_recursive(NAME) \
    __libc_lock_trylock_recursive (NAME)
  #define __rtld_lock_lock_recursive(NAME) \
    __libc_lock_lock_recursive(NAME)
  #define __rtld_lock_unlock_recursive(NAME) \
    __libc_lock_unlock_recursive (NAME)
  
  
  /* XXX for now */
  #define __libc_rwlock_define		__libc_lock_define
  #define __libc_rwlock_define_initialized __libc_lock_define_initialized
  #define __libc_rwlock_init		__libc_lock_init
  #define __libc_rwlock_fini		__libc_lock_fini
  #define __libc_rwlock_rdlock		__libc_lock_lock
  #define __libc_rwlock_wrlock		__libc_lock_lock
  #define __libc_rwlock_tryrdlock		__libc_lock_trylock
  #define __libc_rwlock_trywrlock		__libc_lock_trylock
  #define __libc_rwlock_unlock		__libc_lock_unlock
  
  
  /* Start a critical region with a cleanup function */
  #define __libc_cleanup_region_start(DOIT, FCT, ARG)			    \
  {									    \
    typeof (***(FCT)) *__save_FCT = (DOIT) ? (FCT) : 0;			    \
    typeof (ARG) __save_ARG = ARG;					    \
    /* close brace is in __libc_cleanup_region_end below. */
  
  /* End a critical region started with __libc_cleanup_region_start. */
  #define __libc_cleanup_region_end(DOIT)					    \
    if ((DOIT) && __save_FCT != 0)					    \
      (*__save_FCT)(__save_ARG);						    \
  }
  
  /* Sometimes we have to exit the block in the middle.  */
  #define __libc_cleanup_end(DOIT)					    \
    if ((DOIT) && __save_FCT != 0)					    \
      (*__save_FCT)(__save_ARG);						    \
  
  #define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
  #define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
  
  #if (_CTHREADS_ - 0)
  
  /* Use mutexes as once control variables. */
  
  struct __libc_once
    {
      __libc_lock_t lock;
      int done;
    };
  
  #define __libc_once_define(CLASS,NAME) \
    CLASS struct __libc_once NAME = { MUTEX_INITIALIZER, 0 }
  
  /* Call handler iff the first call.  */
  #define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
    do {									      \
      __libc_lock_lock (ONCE_CONTROL.lock);				      \
      if (!ONCE_CONTROL.done)						      \
        (INIT_FUNCTION) ();						      \
      ONCE_CONTROL.done = 1;						      \
      __libc_lock_unlock (ONCE_CONTROL.lock);				      \
    } while (0)
  
  /* Get once control variable.  */
  #define __libc_once_get(ONCE_CONTROL)	((ONCE_CONTROL).done != 0)
  
  #ifdef _LIBC
  /* We need portable names for some functions.  E.g., when they are
     used as argument to __libc_cleanup_region_start.  */
  #define __libc_mutex_unlock __mutex_unlock
  #endif
  
  /* Type for key of thread specific data.  */
  typedef cthread_key_t __libc_key_t;
  
  #define __libc_key_create(KEY,DEST) cthread_keycreate (KEY)
  #define __libc_setspecific(KEY,VAL) cthread_setspecific (KEY, VAL)
  void *__libc_getspecific (__libc_key_t key);
  
  #endif /* _CTHREADS_ */
  
  #endif	/* bits/libc-lock.h */
  