/* Posix threads interface */ #include #include #if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR) #define destructor xxdestructor #endif #include #if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR) #undef destructor #endif #include /* The POSIX spec says that implementations supporting the sem_* family of functions must indicate this by defining _POSIX_SEMAPHORES. */ #ifdef _POSIX_SEMAPHORES #include #include #endif /* try to determine what version of the Pthread Standard is installed. * this is important, since all sorts of parameter types changed from * draft to draft and there are several (incompatible) drafts in * common use. these macros are a start, at least. * 12 May 1997 -- david arnold */ #if defined(__ultrix) && defined(__mips) && defined(_DECTHREADS_) /* _DECTHREADS_ is defined in cma.h which is included by pthread.h */ # define PY_PTHREAD_D4 # error Systems with PY_PTHREAD_D4 are unsupported. See README. #elif defined(__osf__) && defined (__alpha) /* _DECTHREADS_ is defined in cma.h which is included by pthread.h */ # if !defined(_PTHREAD_ENV_ALPHA) || defined(_PTHREAD_USE_D4) || defined(PTHREAD_USE_D4) # define PY_PTHREAD_D4 # error Systems with PY_PTHREAD_D4 are unsupported. See README. # else # define PY_PTHREAD_STD # endif #elif defined(_AIX) /* SCHED_BG_NP is defined if using AIX DCE pthreads * but it is unsupported by AIX 4 pthreads. Default * attributes for AIX 4 pthreads equal to NULL. For * AIX DCE pthreads they should be left unchanged. */ # if !defined(SCHED_BG_NP) # define PY_PTHREAD_STD # else # define PY_PTHREAD_D7 # error Systems with PY_PTHREAD_D7 are unsupported. See README. # endif #elif defined(__DGUX) # define PY_PTHREAD_D6 # error Systems with PY_PTHREAD_D6 are unsupported. See README. #elif defined(__hpux) && defined(_DECTHREADS_) # define PY_PTHREAD_D4 # error Systems with PY_PTHREAD_D4 are unsupported. See README. #else /* Default case */ # define PY_PTHREAD_STD #endif /* set default attribute object for different versions */ #if defined(PY_PTHREAD_D4) || defined(PY_PTHREAD_D7) #if !defined(pthread_attr_default) # define pthread_attr_default pthread_attr_default #endif #if !defined(pthread_mutexattr_default) # define pthread_mutexattr_default pthread_mutexattr_default #endif #if !defined(pthread_condattr_default) # define pthread_condattr_default pthread_condattr_default #endif #elif defined(PY_PTHREAD_STD) || defined(PY_PTHREAD_D6) #if !defined(pthread_attr_default) # define pthread_attr_default ((pthread_attr_t *)NULL) #endif #if !defined(pthread_mutexattr_default) # define pthread_mutexattr_default ((pthread_mutexattr_t *)NULL) #endif #if !defined(pthread_condattr_default) # define pthread_condattr_default ((pthread_condattr_t *)NULL) #endif #endif /* Whether or not to use semaphores directly rather than emulating them with * mutexes and condition variables: */ #if defined(_POSIX_SEMAPHORES) && !defined(HAVE_BROKEN_POSIX_SEMAPHORES) # define USE_SEMAPHORES #else # undef USE_SEMAPHORES #endif /* On platforms that don't use standard POSIX threads pthread_sigmask() * isn't present. DEC threads uses sigprocmask() instead as do most * other UNIX International compliant systems that don't have the full * pthread implementation. */ #if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK) # define SET_THREAD_SIGMASK pthread_sigmask #else # define SET_THREAD_SIGMASK sigprocmask #endif /* A pthread mutex isn't sufficient to model the Python lock type * because, according to Draft 5 of the docs (P1003.4a/D5), both of the * following are undefined: * -> a thread tries to lock a mutex it already has locked * -> a thread tries to unlock a mutex locked by a different thread * pthread mutexes are designed for serializing threads over short pieces * of code anyway, so wouldn't be an appropriate implementation of * Python's locks regardless. * * The pthread_lock struct implements a Python lock as a "locked?" bit * and a pair. In general, if the bit can be acquired * instantly, it is, else the pair is used to block the thread until the * bit is cleared. 9 May 1994 tim@ksr.com */ typedef struct { char locked; /* 0=unlocked, 1=locked */ /* a pair to handle an acquire of a locked lock */ pthread_cond_t lock_released; pthread_mutex_t mut; } pthread_lock; #define CHECK_STATUS(name) if (status != 0) { perror(name); error = 1; } /* * Initialization. */ #ifdef _HAVE_BSDI static void _noop(void) { } static void PyThread__init_thread(void) { /* DO AN INIT BY STARTING THE THREAD */ static int dummy = 0; pthread_t thread1; pthread_create(&thread1, NULL, (void *) _noop, &dummy); pthread_join(thread1, NULL); } #else /* !_HAVE_BSDI */ static void PyThread__init_thread(void) { #if defined(_AIX) && defined(__GNUC__) pthread_init(); #endif } #endif /* !_HAVE_BSDI */ /* * Thread support. */ long PyThread_start_new_thread(void (*func)(void *), void *arg) { pthread_t th; int status; sigset_t oldmask, newmask; #if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED) pthread_attr_t attrs; #endif dprintf(("PyThread_start_new_thread called\n")); if (!initialized) PyThread_init_thread(); #if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED) pthread_attr_init(&attrs); #endif #ifdef THREAD_STACK_SIZE pthread_attr_setstacksize(&attrs, THREAD_STACK_SIZE); #endif #ifdef PTHREAD_SYSTEM_SCHED_SUPPORTED pthread_attr_setscope(&attrs, PTHREAD_SCOPE_SYSTEM); #endif /* Mask all signals in the current thread before creating the new * thread. This causes the new thread to start with all signals * blocked. */ sigfillset(&newmask); SET_THREAD_SIGMASK(SIG_BLOCK, &newmask, &oldmask); status = pthread_create(&th, #if defined(PY_PTHREAD_D4) pthread_attr_default, (pthread_startroutine_t)func, (pthread_addr_t)arg #elif defined(PY_PTHREAD_D6) pthread_attr_default, (void* (*)(void *))func, arg #elif defined(PY_PTHREAD_D7) pthread_attr_default, func, arg #elif defined(PY_PTHREAD_STD) #if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED) &attrs, #else (pthread_attr_t*)NULL, #endif (void* (*)(void *))func, (void *)arg #endif ); /* Restore signal mask for original thread */ SET_THREAD_SIGMASK(SIG_SETMASK, &oldmask, NULL); #if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED) pthread_attr_destroy(&attrs); #endif if (status != 0) return -1; #if defined(PY_PTHREAD_D4) || defined(PY_PTHREAD_D6) || defined(PY_PTHREAD_D7) pthread_detach(&th); #elif defined(PY_PTHREAD_STD) pthread_detach(th); #endif #if SIZEOF_PTHREAD_T <= SIZEOF_LONG return (long) th; #else return (long) *(long *) &th; #endif } /* XXX This implementation is considered (to quote Tim Peters) "inherently hosed" because: - It does not guanrantee the promise that a non-zero integer is returned. - The cast to long is inherently unsafe. - It is not clear that the 'volatile' (for AIX?) and ugly casting in the latter return statement (for Alpha OSF/1) are any longer necessary. */ long PyThread_get_thread_ident(void) { volatile pthread_t threadid; if (!initialized) PyThread_init_thread(); /* Jump through some hoops for Alpha OSF/1 */ threadid = pthread_self(); #if SIZEOF_PTHREAD_T <= SIZEOF_LONG return (long) threadid; #else return (long) *(long *) &threadid; #endif } static void do_PyThread_exit_thread(int no_cleanup) { dprintf(("PyThread_exit_thread called\n")); if (!initialized) { if (no_cleanup) _exit(0); else exit(0); } } void PyThread_exit_thread(void) { do_PyThread_exit_thread(0); } void PyThread__exit_thread(void) { do_PyThread_exit_thread(1); } #ifndef NO_EXIT_PROG static void do_PyThread_exit_prog(int status, int no_cleanup) { dprintf(("PyThread_exit_prog(%d) called\n", status)); if (!initialized) if (no_cleanup) _exit(status); else exit(status); } void PyThread_exit_prog(int status) { do_PyThread_exit_prog(status, 0); } void PyThread__exit_prog(int status) { do_PyThread_exit_prog(status, 1); } #endif /* NO_EXIT_PROG */ #ifdef USE_SEMAPHORES /* * Lock support. */ PyThread_type_lock PyThread_allocate_lock(void) { sem_t *lock; int status, error = 0; dprintf(("PyThread_allocate_lock called\n")); if (!initialized) PyThread_init_thread(); lock = (sem_t *)malloc(sizeof(sem_t)); if (lock) { status = sem_init(lock,0,1); CHECK_STATUS("sem_init"); if (error) { free((void *)lock); lock = NULL; } } dprintf(("PyThread_allocate_lock() -> %p\n", lock)); return (PyThread_type_lock)lock; } void PyThread_free_lock(PyThread_type_lock lock) { sem_t *thelock = (sem_t *)lock; int status, error = 0; dprintf(("PyThread_free_lock(%p) called\n", lock)); if (!thelock) return; status = sem_destroy(thelock); CHECK_STATUS("sem_destroy"); free((void *)thelock); } /* * As of February 2002, Cygwin thread implementations mistakenly report error * codes in the return value of the sem_ calls (like the pthread_ functions). * Correct implementations return -1 and put the code in errno. This supports * either. */ static int fix_status(int status) { return (status == -1) ? errno : status; } int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag) { int success; sem_t *thelock = (sem_t *)lock; int status, error = 0; dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag)); do { if (waitflag) status = fix_status(sem_wait(thelock)); else status = fix_status(sem_trywait(thelock)); } while (status == EINTR); /* Retry if interrupted by a signal */ if (waitflag) { CHECK_STATUS("sem_wait"); } else if (status != EAGAIN) { CHECK_STATUS("sem_trywait"); } success = (status == 0) ? 1 : 0; dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success)); return success; } void PyThread_release_lock(PyThread_type_lock lock) { sem_t *thelock = (sem_t *)lock; int status, error = 0; dprintf(("PyThread_release_lock(%p) called\n", lock)); status = sem_post(thelock); CHECK_STATUS("sem_post"); } #else /* USE_SEMAPHORES */ /* * Lock support. */ PyThread_type_lock PyThread_allocate_lock(void) { pthread_lock *lock; int status, error = 0; dprintf(("PyThread_allocate_lock called\n")); if (!initialized) PyThread_init_thread(); lock = (pthread_lock *) malloc(sizeof(pthread_lock)); memset((void *)lock, '\0', sizeof(pthread_lock)); if (lock) { lock->locked = 0; status = pthread_mutex_init(&lock->mut, pthread_mutexattr_default); CHECK_STATUS("pthread_mutex_init"); status = pthread_cond_init(&lock->lock_released, pthread_condattr_default); CHECK_STATUS("pthread_cond_init"); if (error) { free((void *)lock); lock = 0; } } dprintf(("PyThread_allocate_lock() -> %p\n", lock)); return (PyThread_type_lock) lock; } void PyThread_free_lock(PyThread_type_lock lock) { pthread_lock *thelock = (pthread_lock *)lock; int status, error = 0; dprintf(("PyThread_free_lock(%p) called\n", lock)); status = pthread_mutex_destroy( &thelock->mut ); CHECK_STATUS("pthread_mutex_destroy"); status = pthread_cond_destroy( &thelock->lock_released ); CHECK_STATUS("pthread_cond_destroy"); free((void *)thelock); } int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag) { int success; pthread_lock *thelock = (pthread_lock *)lock; int status, error = 0; dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag)); status = pthread_mutex_lock( &thelock->mut ); CHECK_STATUS("pthread_mutex_lock[1]"); success = thelock->locked == 0; if ( !success && waitflag ) { /* continue trying until we get the lock */ /* mut must be locked by me -- part of the condition * protocol */ while ( thelock->locked ) { status = pthread_cond_wait(&thelock->lock_released, &thelock->mut); CHECK_STATUS("pthread_cond_wait"); } success = 1; } if (success) thelock->locked = 1; status = pthread_mutex_unlock( &thelock->mut ); CHECK_STATUS("pthread_mutex_unlock[1]"); if (error) success = 0; dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success)); return success; } void PyThread_release_lock(PyThread_type_lock lock) { pthread_lock *thelock = (pthread_lock *)lock; int status, error = 0; dprintf(("PyThread_release_lock(%p) called\n", lock)); status = pthread_mutex_lock( &thelock->mut ); CHECK_STATUS("pthread_mutex_lock[3]"); thelock->locked = 0; status = pthread_mutex_unlock( &thelock->mut ); CHECK_STATUS("pthread_mutex_unlock[3]"); /* wake up someone (anyone, if any) waiting on the lock */ status = pthread_cond_signal( &thelock->lock_released ); CHECK_STATUS("pthread_cond_signal"); } #endif /* USE_SEMAPHORES */