231 lines
7.5 KiB
C
231 lines
7.5 KiB
C
/* libc-internal interface for mutex locks. Mach cthreads version.
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Copyright (C) 1996-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _LIBC_LOCK_H
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#define _LIBC_LOCK_H 1
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#ifdef _LIBC
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#include <tls.h>
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#include <lowlevellock.h>
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/* The locking here is very inexpensive, even for inlining. */
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#define _IO_lock_inexpensive 1
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typedef unsigned int __libc_lock_t;
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typedef struct
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{
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__libc_lock_t lock;
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int cnt;
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void *owner;
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} __libc_lock_recursive_t;
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typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
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extern char __libc_lock_self0[0];
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#define __libc_lock_owner_self() \
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(__LIBC_NO_TLS () ? (void *)&__libc_lock_self0 : THREAD_SELF)
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#else
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typedef struct __libc_lock_opaque__ __libc_lock_t;
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typedef struct __libc_lock_recursive_opaque__ __libc_lock_recursive_t;
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#endif
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/* Define a lock variable NAME with storage class CLASS. The lock must be
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initialized with __libc_lock_init before it can be used (or define it
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with __libc_lock_define_initialized, below). Use `extern' for CLASS to
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declare a lock defined in another module. In public structure
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definitions you must use a pointer to the lock structure (i.e., NAME
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begins with a `*'), because its storage size will not be known outside
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of libc. */
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#define __libc_lock_define(CLASS,NAME) \
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CLASS __libc_lock_t NAME;
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/* Define an initialized lock variable NAME with storage class CLASS. */
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#define _LIBC_LOCK_INITIALIZER LLL_INITIALIZER
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#define __libc_lock_define_initialized(CLASS,NAME) \
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CLASS __libc_lock_t NAME = LLL_INITIALIZER;
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/* Initialize the named lock variable, leaving it in a consistent, unlocked
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state. */
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#define __libc_lock_init(NAME) (NAME) = LLL_INITIALIZER
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/* Finalize the named lock variable, which must be locked. It cannot be
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used again until __libc_lock_init is called again on it. This must be
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called on a lock variable before the containing storage is reused. */
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#define __libc_lock_fini __libc_lock_unlock
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#define __libc_lock_fini_recursive __libc_lock_unlock_recursive
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#define __rtld_lock_fini_recursive __rtld_lock_unlock_recursive
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/* Lock the named lock variable. */
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#define __libc_lock_lock(NAME) \
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({ lll_lock (&(NAME), 0); 0; })
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/* Lock the named lock variable. */
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#define __libc_lock_trylock(NAME) lll_trylock (&(NAME))
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/* Unlock the named lock variable. */
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#define __libc_lock_unlock(NAME) \
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({ lll_unlock (&(NAME), 0); 0; })
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#define __libc_lock_define_recursive(CLASS,NAME) \
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CLASS __libc_lock_recursive_t NAME;
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#define _LIBC_LOCK_RECURSIVE_INITIALIZER { LLL_INITIALIZER, 0, 0 }
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#define __libc_lock_define_initialized_recursive(CLASS,NAME) \
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CLASS __libc_lock_recursive_t NAME = _LIBC_LOCK_RECURSIVE_INITIALIZER;
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#define __rtld_lock_define_recursive(CLASS,NAME) \
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__libc_lock_define_recursive (CLASS, NAME)
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#define _RTLD_LOCK_RECURSIVE_INITIALIZER \
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_LIBC_LOCK_RECURSIVE_INITIALIZER
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#define __rtld_lock_define_initialized_recursive(CLASS,NAME) \
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__libc_lock_define_initialized_recursive (CLASS, NAME)
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#define __libc_lock_init_recursive(NAME) \
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({ \
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(NAME) = (__libc_lock_recursive_t)_LIBC_LOCK_RECURSIVE_INITIALIZER; \
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0; \
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})
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#define __libc_lock_trylock_recursive(NAME) \
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({ \
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__libc_lock_recursive_t *const __lock = &(NAME); \
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void *__self = __libc_lock_owner_self (); \
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int __r = 0; \
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if (__self == __lock->owner) \
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++__lock->cnt; \
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else if ((__r = lll_trylock (&__lock->lock)) == 0) \
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__lock->owner = __self, __lock->cnt = 1; \
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__r; \
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})
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#define __libc_lock_lock_recursive(NAME) \
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({ \
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__libc_lock_recursive_t *const __lock = &(NAME); \
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void *__self = __libc_lock_owner_self (); \
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if (__self != __lock->owner) \
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{ \
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lll_lock (&__lock->lock, 0); \
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__lock->owner = __self; \
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} \
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++__lock->cnt; \
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(void)0; \
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})
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#define __libc_lock_unlock_recursive(NAME) \
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({ \
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__libc_lock_recursive_t *const __lock = &(NAME); \
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if (--__lock->cnt == 0) \
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{ \
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__lock->owner = 0; \
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lll_unlock (&__lock->lock, 0); \
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} \
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})
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#define __rtld_lock_initialize(NAME) \
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(void) ((NAME) = (__rtld_lock_recursive_t) _RTLD_LOCK_RECURSIVE_INITIALIZER)
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#define __rtld_lock_trylock_recursive(NAME) \
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__libc_lock_trylock_recursive (NAME)
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#define __rtld_lock_lock_recursive(NAME) \
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__libc_lock_lock_recursive(NAME)
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#define __rtld_lock_unlock_recursive(NAME) \
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__libc_lock_unlock_recursive (NAME)
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/* XXX for now */
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#define __libc_rwlock_define __libc_lock_define
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#define __libc_rwlock_define_initialized __libc_lock_define_initialized
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#define __libc_rwlock_init __libc_lock_init
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#define __libc_rwlock_fini __libc_lock_fini
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#define __libc_rwlock_rdlock __libc_lock_lock
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#define __libc_rwlock_wrlock __libc_lock_lock
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#define __libc_rwlock_tryrdlock __libc_lock_trylock
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#define __libc_rwlock_trywrlock __libc_lock_trylock
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#define __libc_rwlock_unlock __libc_lock_unlock
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struct __libc_cleanup_frame
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{
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void (*__fct) (void *);
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void *__argp;
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int __doit;
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};
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__extern_inline void
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__libc_cleanup_fct (struct __libc_cleanup_frame *framep)
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{
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if (framep->__doit)
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framep->__fct (framep->__argp);
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}
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/* Start a critical region with a cleanup function */
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#define __libc_cleanup_region_start(DOIT, FCT, ARG) \
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do \
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{ \
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struct __libc_cleanup_frame __cleanup \
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__attribute__ ((__cleanup__ (__libc_cleanup_fct))) = \
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{ .__fct = (FCT), .__argp = (ARG), .__doit = (DOIT) };
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/* This one closes the brace above. */
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#define __libc_cleanup_region_end(DOIT) \
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__cleanup.__doit = (DOIT); \
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} \
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while (0)
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#define __libc_cleanup_end(DOIT) __cleanup.__doit = (DOIT);
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#define __libc_cleanup_push(fct, arg) __libc_cleanup_region_start (1, fct, arg)
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#define __libc_cleanup_pop(execute) __libc_cleanup_region_end (execute)
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/* Use mutexes as once control variables. */
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struct __libc_once
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{
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__libc_lock_t lock;
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int done;
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};
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#define __libc_once_define(CLASS,NAME) \
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CLASS struct __libc_once NAME = { _LIBC_LOCK_INITIALIZER, 0 }
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/* Call handler iff the first call. */
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#define __libc_once(ONCE_CONTROL, INIT_FUNCTION) \
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do { \
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__libc_lock_lock (ONCE_CONTROL.lock); \
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if (!ONCE_CONTROL.done) \
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(INIT_FUNCTION) (); \
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ONCE_CONTROL.done = 1; \
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__libc_lock_unlock (ONCE_CONTROL.lock); \
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} while (0)
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/* Get once control variable. */
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#define __libc_once_get(ONCE_CONTROL) ((ONCE_CONTROL).done != 0)
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#ifdef _LIBC
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/* We need portable names for some functions. E.g., when they are
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used as argument to __libc_cleanup_region_start. */
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#define __libc_mutex_unlock __libc_lock_unlock
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/* Hide the definitions which are only supposed to be used inside libc in
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a separate file. This file is not present in the installation! */
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# include <libc-lockP.h>
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#endif
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#endif /* libc-lock.h */
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