/* Basic platform-independent macro definitions for mutexes and thread-specific data. Copyright (C) 1996,1997,1998,2000,2001,2002 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Wolfram Gloger , 2001. 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, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ /* $Id$ One out of _LIBC, USE_PTHREADS, USE_THR or USE_SPROC should be defined, otherwise the token NO_THREADS and dummy implementations of the macros will be defined. */ #ifndef _THREAD_M_H #define _THREAD_M_H #undef thread_atfork_static #if defined(_LIBC) /* The GNU C library, a special case of Posix threads */ #include #ifdef PTHREAD_MUTEX_INITIALIZER typedef pthread_t thread_id; /* mutex */ typedef pthread_mutex_t mutex_t; #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER /* Even if not linking with libpthread, ensure usability of mutex as an `in use' flag, see also the NO_THREADS case below. Assume pthread_mutex_t is at least one int wide. */ #define mutex_init(m) \ (__pthread_mutex_init != NULL \ ? __pthread_mutex_init (m, NULL) : (*(int *)(m) = 0)) #define mutex_lock(m) \ (__pthread_mutex_lock != NULL \ ? __pthread_mutex_lock (m) : ((*(int *)(m) = 1), 0)) #define mutex_trylock(m) \ (__pthread_mutex_trylock != NULL \ ? __pthread_mutex_trylock (m) : (*(int *)(m) ? 1 : ((*(int *)(m) = 1), 0))) #define mutex_unlock(m) \ (__pthread_mutex_unlock != NULL \ ? __pthread_mutex_unlock (m) : (*(int*)(m) = 0)) #define thread_atfork(prepare, parent, child) \ (__pthread_atfork != NULL ? __pthread_atfork(prepare, parent, child) : 0) #elif defined(MUTEX_INITIALIZER) /* Assume hurd, with cthreads */ /* Cthreads `mutex_t' is a pointer to a mutex, and malloc wants just the mutex itself. */ #undef mutex_t #define mutex_t struct mutex #undef mutex_init #define mutex_init(m) (__mutex_init(m), 0) #undef mutex_lock #define mutex_lock(m) (__mutex_lock(m), 0) #undef mutex_unlock #define mutex_unlock(m) (__mutex_unlock(m), 0) #define mutex_trylock(m) (!__mutex_trylock(m)) #define thread_atfork(prepare, parent, child) do {} while(0) #define thread_atfork_static(prepare, parent, child) \ text_set_element(_hurd_fork_prepare_hook, prepare); \ text_set_element(_hurd_fork_parent_hook, parent); \ text_set_element(_hurd_fork_child_hook, child); /* No we're *not* using pthreads. */ #define __pthread_initialize ((void (*)(void))0) #else #define NO_THREADS #endif /* MUTEX_INITIALIZER && PTHREAD_MUTEX_INITIALIZER */ #ifndef NO_THREADS /* thread specific data for glibc */ #include typedef int tsd_key_t[1]; /* no key data structure, libc magic does it */ __libc_tsd_define (static, MALLOC) /* declaration/common definition */ #define tsd_key_create(key, destr) ((void) (key)) #define tsd_setspecific(key, data) __libc_tsd_set (MALLOC, (data)) #define tsd_getspecific(key, vptr) ((vptr) = __libc_tsd_get (MALLOC)) #endif #elif defined(USE_PTHREADS) /* Posix threads */ #include typedef pthread_t thread_id; /* mutex */ #if (defined __i386__ || defined __x86_64__) && defined __GNUC__ && \ !defined USE_NO_SPINLOCKS #include /* Use fast inline spinlocks. */ typedef struct { volatile unsigned int lock; int pad0_; } mutex_t; #define MUTEX_INITIALIZER { 0 } #define mutex_init(m) ((m)->lock = 0) static inline int mutex_lock(mutex_t *m) { int cnt = 0, r; struct timespec tm; for(;;) { __asm__ __volatile__ ("xchgl %0, %1" : "=r"(r), "=m"(m->lock) : "0"(1), "m"(m->lock) : "memory"); if(!r) return 0; if(cnt < 50) { sched_yield(); cnt++; } else { tm.tv_sec = 0; tm.tv_nsec = 2000001; nanosleep(&tm, NULL); cnt = 0; } } } static inline int mutex_trylock(mutex_t *m) { int r; __asm__ __volatile__ ("xchgl %0, %1" : "=r"(r), "=m"(m->lock) : "0"(1), "m"(m->lock) : "memory"); return r; } static inline int mutex_unlock(mutex_t *m) { m->lock = 0; __asm __volatile ("" : "=m" (m->lock) : "0" (m->lock)); return 0; } #else /* Normal pthread mutex. */ typedef pthread_mutex_t mutex_t; #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER #define mutex_init(m) pthread_mutex_init(m, NULL) #define mutex_lock(m) pthread_mutex_lock(m) #define mutex_trylock(m) pthread_mutex_trylock(m) #define mutex_unlock(m) pthread_mutex_unlock(m) #endif /* (__i386__ || __x86_64__) && __GNUC__ && !USE_NO_SPINLOCKS */ /* thread specific data */ #if defined(__sgi) || defined(USE_TSD_DATA_HACK) /* Hack for thread-specific data, e.g. on Irix 6.x. We can't use pthread_setspecific because that function calls malloc() itself. The hack only works when pthread_t can be converted to an integral type. */ typedef void *tsd_key_t[256]; #define tsd_key_create(key, destr) do { \ int i; \ for(i=0; i<256; i++) (*key)[i] = 0; \ } while(0) #define tsd_setspecific(key, data) \ (key[(unsigned)pthread_self() % 256] = (data)) #define tsd_getspecific(key, vptr) \ (vptr = key[(unsigned)pthread_self() % 256]) #else typedef pthread_key_t tsd_key_t; #define tsd_key_create(key, destr) pthread_key_create(key, destr) #define tsd_setspecific(key, data) pthread_setspecific(key, data) #define tsd_getspecific(key, vptr) (vptr = pthread_getspecific(key)) #endif /* at fork */ #define thread_atfork(prepare, parent, child) \ pthread_atfork(prepare, parent, child) #elif USE_THR /* Solaris threads */ #include typedef thread_t thread_id; #define MUTEX_INITIALIZER { 0 } #define mutex_init(m) mutex_init(m, USYNC_THREAD, NULL) /* * Hack for thread-specific data on Solaris. We can't use thr_setspecific * because that function calls malloc() itself. */ typedef void *tsd_key_t[256]; #define tsd_key_create(key, destr) do { \ int i; \ for(i=0; i<256; i++) (*key)[i] = 0; \ } while(0) #define tsd_setspecific(key, data) (key[(unsigned)thr_self() % 256] = (data)) #define tsd_getspecific(key, vptr) (vptr = key[(unsigned)thr_self() % 256]) #define thread_atfork(prepare, parent, child) do {} while(0) #elif USE_SPROC /* SGI sproc() threads */ #include #include #include #include typedef int thread_id; typedef abilock_t mutex_t; #define MUTEX_INITIALIZER { 0 } #define mutex_init(m) init_lock(m) #define mutex_lock(m) (spin_lock(m), 0) #define mutex_trylock(m) acquire_lock(m) #define mutex_unlock(m) release_lock(m) typedef int tsd_key_t; int tsd_key_next; #define tsd_key_create(key, destr) ((*key) = tsd_key_next++) #define tsd_setspecific(key, data) (((void **)(&PRDA->usr_prda))[key] = data) #define tsd_getspecific(key, vptr) (vptr = ((void **)(&PRDA->usr_prda))[key]) #define thread_atfork(prepare, parent, child) do {} while(0) #else /* no _LIBC or USE_... are defined */ #define NO_THREADS #endif /* defined(_LIBC) */ #ifdef NO_THREADS /* No threads, provide dummy macros */ typedef int thread_id; /* The mutex functions used to do absolutely nothing, i.e. lock, trylock and unlock would always just return 0. However, even without any concurrently active threads, a mutex can be used legitimately as an `in use' flag. To make the code that is protected by a mutex async-signal safe, these macros would have to be based on atomic test-and-set operations, for example. */ typedef int mutex_t; #define MUTEX_INITIALIZER 0 #define mutex_init(m) (*(m) = 0) #define mutex_lock(m) ((*(m) = 1), 0) #define mutex_trylock(m) (*(m) ? 1 : ((*(m) = 1), 0)) #define mutex_unlock(m) (*(m) = 0) typedef void *tsd_key_t; #define tsd_key_create(key, destr) do {} while(0) #define tsd_setspecific(key, data) ((key) = (data)) #define tsd_getspecific(key, vptr) (vptr = (key)) #define thread_atfork(prepare, parent, child) do {} while(0) #endif /* defined(NO_THREADS) */ #endif /* !defined(_THREAD_M_H) */