diff options
Diffstat (limited to 'lib/qpthreads.h')
| -rw-r--r-- | lib/qpthreads.h | 166 |
1 files changed, 110 insertions, 56 deletions
diff --git a/lib/qpthreads.h b/lib/qpthreads.h index 5a442cc7..49a7c1e3 100644 --- a/lib/qpthreads.h +++ b/lib/qpthreads.h @@ -35,6 +35,10 @@ #define Inline static inline #endif +#ifndef private +#define private extern +#endif + /*============================================================================== * Quagga Pthread Interface -- qpt_xxxx * @@ -57,6 +61,22 @@ #endif /*============================================================================== + * Global Switch -- this allows the library to be run WITHOUT pthreads ! + * + * Nearly every qpthreads function is a NOP if !qpthreads_enabled. + * + * Early in the morning a decision may be made to enable qpthreads -- that must + * be done before any threads are created (or will zabort) and before any + * mutexes and condition variables are initialised. + * + * Use: qpthreads_enabled -- to test for the enabled-ness + * qpthreads_enabled_freeze -- to test and freeze unset if not yet enabled + */ + +#define qpthreads_enabled ((const int)qpthreads_enabled_flag) +#define qpthreads_enabled_freeze qpt_freeze_qpthreads_enabled() + +/*============================================================================== * Data types */ @@ -66,8 +86,13 @@ typedef pthread_cond_t qpt_cond_t ; typedef pthread_attr_t qpt_thread_attr_t ; +typedef qpt_mutex_t* qpt_mutex ; +typedef qpt_cond_t* qpt_cond ; + /*============================================================================== * Thread Creation -- see qpthreads.c for further discussion. + * + * NB: it is a FATAL error to attempt these if !qpthreads_enabled. */ enum qpt_attr_options @@ -92,19 +117,30 @@ enum qpt_attr_options #define qpt_attr_known ( qpt_attr_detached | qpt_attr_sched_setting ) -extern qpt_thread_attr_t* +extern qpt_thread_attr_t* /* FATAL error if !qpthreads_enabled */ qpt_thread_attr_init(qpt_thread_attr_t* attr, enum qpt_attr_options opts, int scope, int policy, int priority) ; -extern qpt_thread_t +extern qpt_thread_t /* FATAL error if !qpthreads_enabled */ qpt_thread_create(void* (*start)(void*), void* arg, qpt_thread_attr_t* attr) ; /*============================================================================== - * Thread self knowledge. + * qpthreads_enabled support -- NOT FOR PUBLIC CONSUMPTION ! + */ +private int qpthreads_enabled_flag ; /* DO NOT WRITE TO THIS PLEASE */ + +private void +qpt_set_qpthreads_enabled(int how) ; /* qpthreads_enabled := how */ + +private int +qpt_freeze_qpthreads_enabled(void) ; /* get and freeze qpthreads_enabled */ + +/*============================================================================== + * Thread self knowledge -- returns 'NULL' if !qpthreads_enabled */ Inline qpt_thread_t qpt_thread_self(void) { - return pthread_self() ; + return qpthreads_enabled ? pthread_self() : (qpt_thread_t)NULL; } ; /*============================================================================== @@ -127,6 +163,10 @@ Inline qpt_thread_t qpt_thread_self(void) * If _DEFAULT is faster than _NORMAL, then QPT_MUTEX_TYPE_DEFAULT may be * used to override this choice. * + * NB: if NOT qpthreads_enabled, all mutex actions are EMPTY. This allows + * code to be made thread-safe for when pthreads is running, but to work + * perfectly well without pthreads. + * * NB: do not (currently) support pthread_mutex_timedlock(). */ @@ -149,23 +189,25 @@ enum qpt_mutex_options # define QPT_MUTEX_TYPE PTHREAD_MUTEX_ERRORCHECK #endif -extern qpt_mutex_t* -qpt_mutex_init(qpt_mutex_t* mx, enum qpt_mutex_options opts) ; +extern qpt_mutex /* freezes qpthreads_enabled */ +qpt_mutex_init_new(qpt_mutex mx, enum qpt_mutex_options opts) ; -extern qpt_mutex_t* -qpt_mutex_destroy(qpt_mutex_t* mx, int free_mutex) ; +#define qpt_mutex_init qpt_mutex_init_new + +extern qpt_mutex /* do nothing if !qpthreads_enabled */ +qpt_mutex_destroy(qpt_mutex mx, int free_mutex) ; #define qpt_mutex_destroy_keep(mx) qpt_mutex_destroy(mx, 0) #define qpt_mutex_destroy_free(mx) qpt_mutex_destroy(mx, 1) Inline void -qpt_mutex_lock(qpt_mutex_t* mx) ; /* do nothing if mx == NULL */ +qpt_mutex_lock(qpt_mutex mx) ; /* do nothing if !qpthreads_enabled */ Inline int -qpt_mutex_trylock(qpt_mutex_t* mx) ; /* do nothing if mx == NULL */ +qpt_mutex_trylock(qpt_mutex mx) ; /* always succeeds if !qpthreads_enabled */ Inline void -qpt_mutex_unlock(qpt_mutex_t* mx) ; /* do nothing if mx == NULL */ +qpt_mutex_unlock(qpt_mutex mx) ; /* do nothing if !qpthreads_enabled */ /*============================================================================== * Condition Variable handling @@ -188,6 +230,10 @@ qpt_mutex_unlock(qpt_mutex_t* mx) ; /* do nothing if mx == NULL */ * * NB: static initialisation of condition variables is not supported, to avoid * confusion between the standard default and Quagga's default. + + * NB: if NOT qpthreads_enabled, all condition actions are EMPTY. This allows + * code to be made thread-safe for when pthreads is running, but to work + * perfectly well without pthreads. */ #ifndef QPT_COND_CLOCK_ID @@ -205,41 +251,41 @@ enum qpt_cond_options qpt_cond_quagga = 0x0000, /* Quagga's default */ } ; -extern qpt_cond_t* -qpt_cond_init(qpt_cond_t* cv, enum qpt_cond_options opts) ; +extern qpt_cond /* freezes qpthreads_enabled */ +qpt_cond_init_new(qpt_cond cv, enum qpt_cond_options opts) ; -extern qpt_cond_t* -qpt_cond_destroy(qpt_cond_t* cv, int free_cond) ; +extern qpt_cond /* do nothing if !qpthreads_enabled */ +qpt_cond_destroy(qpt_cond cv, int free_cond) ; #define qpt_cond_destroy_keep(cv) qpt_cond_destroy(cv, 0) #define qpt_cond_destroy_free(cv) qpt_cond_destroy(cv, 1) -Inline void -qpt_cond_wait(qpt_cond_t* cv, qpt_mutex_t* mx) ; +Inline void /* do nothing if !qpthreads_enabled */ +qpt_cond_wait(qpt_cond cv, qpt_mutex mx) ; -extern int -qpt_cond_timedwait(qpt_cond_t* cv, qpt_mutex_t* mx, qtime_mono_t timeout_time) ; +extern int /* returns !qpthreads_enabled */ +qpt_cond_timedwait(qpt_cond cv, qpt_mutex mx, qtime_mono_t timeout_time) ; -Inline void -qpt_cond_signal(qpt_cond_t* cv) ; +Inline void /* do nothing if !qpthreads_enabled */ +qpt_cond_signal(qpt_cond cv) ; -Inline void -qpt_cond_broadcast(qpt_cond_t* cv) ; +Inline void /* do nothing if !qpthreads_enabled */ +qpt_cond_broadcast(qpt_cond cv) ; /*============================================================================== * Mutex inline functions */ -/* Lock given mutex. +/* Lock given mutex -- or do nothing if !qpthreads_enabled. * * Unless both NCHECK_QPTHREADS and NDEBUG are defined, checks that the * return value is valid -- zabort_errno if it isn't. */ Inline void -qpt_mutex_lock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ +qpt_mutex_lock(qpt_mutex mx) { - if (mx != NULL) + if (qpthreads_enabled) { #if defined(NDEBUG) && defined(NDEBUG_QPTHREADS) pthread_mutex_lock(mx) ; @@ -251,7 +297,7 @@ qpt_mutex_lock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ } ; } ; -/* Try to lock given mutex. +/* Try to lock given mutex -- every time a winner if !qpthreads_enabled. * * Returns: lock succeeded (1 => have locked, 0 => unable to lock). * @@ -259,9 +305,9 @@ qpt_mutex_lock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ */ Inline int -qpt_mutex_trylock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ +qpt_mutex_trylock(qpt_mutex mx) { - if (mx != NULL) + if (qpthreads_enabled) { int err = pthread_mutex_trylock(mx) ; if (err == 0) @@ -270,19 +316,20 @@ qpt_mutex_trylock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ return 0 ; /* unable to lock */ zabort_err("pthread_mutex_trylock failed", err) ; - /* crunch */ - } ; + } + else + return 1 ; } ; -/* Unlock given mutex. +/* Unlock given mutex -- or do nothing if !qpthreads_enabled. * * Unless both NCHECK_QPTHREADS and NDEBUG are defined, checks that the * return value is valid -- zabort_errno if it isn't. */ Inline void -qpt_mutex_unlock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ +qpt_mutex_unlock(qpt_mutex mx) { - if (mx != NULL) + if (qpthreads_enabled) { #if defined(NDEBUG) && defined(NDEBUG_QPTHREADS) pthread_mutex_unlock(mx) ; @@ -298,66 +345,73 @@ qpt_mutex_unlock(qpt_mutex_t* mx) /* do nothing if mx == NULL */ * Condition variable inline functions */ -/* Wait for given condition variable. +/* Wait for given condition variable -- do nothing if !qpthreads_enabled * * Unless both NCHECK_QPTHREADS and NDEBUG are defined, checks that the * return value is valid -- zabort_errno if it isn't. */ - Inline void -qpt_cond_wait(qpt_cond_t* cv, qpt_mutex_t* mx) +qpt_cond_wait(qpt_cond cv, qpt_mutex mx) { + if (qpthreads_enabled) + { #if defined(NDEBUG) && defined(NDEBUG_QPTHREADS) - pthread_cond_wait(cv, mx) ; + pthread_cond_wait(cv, mx) ; #else - int err = pthread_cond_wait(cv, mx) ; - if (err != 0) - zabort_err("pthread_cond_wait failed", err) ; + int err = pthread_cond_wait(cv, mx) ; + if (err != 0) + zabort_err("pthread_cond_wait failed", err) ; #endif + } ; } ; -/* Signal given condition. +/* Signal given condition -- do nothing if !qpthreads_enabled * * Unless both NCHECK_QPTHREADS and NDEBUG are defined, checks that the * return value is valid -- zabort_errno if it isn't. */ - Inline void -qpt_cond_signal(qpt_cond_t* cv) +qpt_cond_signal(qpt_cond cv) { + if (qpthreads_enabled) + { #if defined(NDEBUG) && defined(NDEBUG_QPTHREADS) - pthread_cond_signal(cv) ; + pthread_cond_signal(cv) ; #else - int err = pthread_cond_signal(cv) ; - if (err != 0) - zabort_err("pthread_cond_signal failed", err) ; + int err = pthread_cond_signal(cv) ; + if (err != 0) + zabort_err("pthread_cond_signal failed", err) ; #endif + } ; } ; -/* Broadcast given condition. +/* Broadcast given condition -- do nothing if !qpthreads_enabled * * Unless both NCHECK_QPTHREADS and NDEBUG are defined, checks that the * return value is valid -- zabort_errno if it isn't. */ Inline void -qpt_cond_broadcast(qpt_cond_t* cv) +qpt_cond_broadcast(qpt_cond cv) { + if (qpthreads_enabled) + { #if defined(NDEBUG) && defined(NDEBUG_QPTHREADS) - pthread_cond_broadcast(cv) ; + pthread_cond_broadcast(cv) ; #else - int err = pthread_cond_broadcast(cv) ; - if (err != 0) - zabort_err("pthread_cond_broadcast failed", err) ; + int err = pthread_cond_broadcast(cv) ; + if (err != 0) + zabort_err("pthread_cond_broadcast failed", err) ; #endif + } ; } ; /*============================================================================== * Signal Handling. */ -void +void /* FATAL error if !qpthreads_enabled */ qpt_thread_sigmask(int how, const sigset_t* set, sigset_t* oset) ; -void +void /* FATAL error if !qpthreads_enabled */ qpt_thread_signal(qpt_thread_t thread, int signum) ; #endif /* _ZEBRA_QPTHREADS_H */ |