X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=src%2Fside.c;h=ec5fdbf81b367de829522435f1509a02e5c0b74b;hb=f8188f94f6e17919ca75063e4d43faca0fd03af8;hp=0460860bd32666bfd5e6b9fe33d693f8fd1b68b9;hpb=b59abc699f5426cda5954a7bea8eed0d40852864;p=libside.git diff --git a/src/side.c b/src/side.c index 0460860..ec5fdbf 100644 --- a/src/side.c +++ b/src/side.c @@ -6,16 +6,36 @@ #include #include -#include "tracer.h" #include "rcu.h" #include "list.h" /* Top 8 bits reserved for kernel tracer use. */ -#define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000 -#define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000 +#if SIDE_BITS_PER_LONG == 64 +# define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF00000000000000ULL +# define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x8000000000000000ULL -/* Allow 2^24 tracer callbacks to be registered on an event. */ -#define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFF +/* Allow 2^56 tracer references on an event. */ +# define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFFFFFFFFFFULL +#else +# define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000UL +# define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000UL + +/* Allow 2^24 tracer references on an event. */ +# define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFFUL +#endif + +struct side_events_register_handle { + struct side_list_node node; + struct side_event_description **events; + uint32_t nr_events; +}; + +struct side_tracer_handle { + struct side_list_node node; + void (*cb)(enum side_tracer_notification notif, + struct side_event_description **events, uint32_t nr_events, void *priv); + void *priv; +}; static struct side_rcu_gp_state rcu_gp; @@ -23,88 +43,89 @@ static struct side_rcu_gp_state rcu_gp; * Lazy initialization for early use within library constructors. */ static bool initialized; +/* + * Do not register/unregister any more events after destructor. + */ +static bool finalized; -static pthread_mutex_t side_lock = PTHREAD_MUTEX_INITIALIZER; - -static DEFINE_SIDE_LIST_HEAD(side_list); +/* + * Recursive mutex to allow tracer callbacks to use the side API. + */ +static pthread_mutex_t side_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; -static -void side_init(void) - __attribute__((constructor)); +static DEFINE_SIDE_LIST_HEAD(side_events_list); +static DEFINE_SIDE_LIST_HEAD(side_tracer_list); /* * The empty callback has a NULL function callback pointer, which stops * iteration on the array of callbacks immediately. */ -const struct side_callback side_empty_callback; +const struct side_callback side_empty_callback = { }; -void side_call(const struct side_event_description *desc, const struct side_arg_vec_description *sav_desc) +void side_call(const struct side_event_description *desc, const struct side_arg_vec *side_arg_vec) { + struct side_event_state *event_state; + struct side_rcu_read_state rcu_read_state; const struct side_callback *side_cb; - unsigned int rcu_period; - uint32_t enabled; + uintptr_t enabled; + if (side_unlikely(finalized)) + return; if (side_unlikely(!initialized)) side_init(); if (side_unlikely(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) { printf("ERROR: unexpected variadic event description\n"); abort(); } - enabled = __atomic_load_n(desc->enabled, __ATOMIC_RELAXED); + event_state = side_ptr_get(desc->state); + enabled = __atomic_load_n(&event_state->enabled, __ATOMIC_RELAXED); if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) { // TODO: call kernel write. } - if (side_unlikely(!(enabled & SIDE_EVENT_ENABLED_USER_MASK))) - return; - - //TODO: replace tracer_call by rcu iteration on list of registered callbacks - tracer_call(desc, sav_desc, NULL); - - rcu_period = side_rcu_read_begin(&rcu_gp); - for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call != NULL; side_cb++) - side_cb->u.call(desc, sav_desc, side_cb->priv); - side_rcu_read_end(&rcu_gp, rcu_period); + side_rcu_read_begin(&rcu_gp, &rcu_read_state); + for (side_cb = side_rcu_dereference(event_state->callbacks); side_cb->u.call != NULL; side_cb++) + side_cb->u.call(desc, side_arg_vec, side_cb->priv); + side_rcu_read_end(&rcu_gp, &rcu_read_state); } void side_call_variadic(const struct side_event_description *desc, - const struct side_arg_vec_description *sav_desc, - const struct side_arg_dynamic_event_struct *var_struct) + const struct side_arg_vec *side_arg_vec, + const struct side_arg_dynamic_struct *var_struct) { + struct side_event_state *event_state; + struct side_rcu_read_state rcu_read_state; const struct side_callback *side_cb; - unsigned int rcu_period; - uint32_t enabled; + uintptr_t enabled; + if (side_unlikely(finalized)) + return; if (side_unlikely(!initialized)) side_init(); if (side_unlikely(!(desc->flags & SIDE_EVENT_FLAG_VARIADIC))) { printf("ERROR: unexpected non-variadic event description\n"); abort(); } - enabled = __atomic_load_n(desc->enabled, __ATOMIC_RELAXED); + event_state = side_ptr_get(desc->state); + enabled = __atomic_load_n(&event_state->enabled, __ATOMIC_RELAXED); if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) { // TODO: call kernel write. } - if (side_unlikely(!(enabled & SIDE_EVENT_ENABLED_USER_MASK))) - return; - - //TODO: replace tracer_call by rcu iteration on list of registered callbacks - tracer_call_variadic(desc, sav_desc, var_struct, NULL); - - rcu_period = side_rcu_read_begin(&rcu_gp); - for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call_variadic != NULL; side_cb++) - side_cb->u.call_variadic(desc, sav_desc, var_struct, side_cb->priv); - side_rcu_read_end(&rcu_gp, rcu_period); + side_rcu_read_begin(&rcu_gp, &rcu_read_state); + for (side_cb = side_rcu_dereference(event_state->callbacks); side_cb->u.call_variadic != NULL; side_cb++) + side_cb->u.call_variadic(desc, side_arg_vec, var_struct, side_cb->priv); + side_rcu_read_end(&rcu_gp, &rcu_read_state); } static const struct side_callback *side_tracer_callback_lookup( const struct side_event_description *desc, - void (*call)(), void *priv) + void *call, void *priv) { + struct side_event_state *event_state = side_ptr_get(desc->state); const struct side_callback *cb; - for (cb = desc->callbacks; cb->u.call != NULL; cb++) { - if (cb->u.call == call && cb->priv == priv) + for (cb = event_state->callbacks; cb->u.call != NULL; cb++) { + if ((void *) cb->u.call == call && cb->priv == priv) return cb; } return NULL; @@ -112,17 +133,23 @@ const struct side_callback *side_tracer_callback_lookup( static int _side_tracer_callback_register(struct side_event_description *desc, - void (*call)(), void *priv) + void *call, void *priv) { + struct side_event_state *event_state; struct side_callback *old_cb, *new_cb; int ret = SIDE_ERROR_OK; uint32_t old_nr_cb; if (!call) return SIDE_ERROR_INVAL; + if (finalized) + return SIDE_ERROR_EXITING; + if (!initialized) + side_init(); pthread_mutex_lock(&side_lock); - old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK; - if (old_nr_cb == SIDE_EVENT_ENABLED_USER_MASK) { + event_state = side_ptr_get(desc->state); + old_nr_cb = desc->nr_callbacks; + if (old_nr_cb == UINT32_MAX) { ret = SIDE_ERROR_INVAL; goto unlock; } @@ -131,7 +158,7 @@ int _side_tracer_callback_register(struct side_event_description *desc, ret = SIDE_ERROR_EXIST; goto unlock; } - old_cb = (struct side_callback *) desc->callbacks; + old_cb = (struct side_callback *) event_state->callbacks; /* old_nr_cb + 1 (new cb) + 1 (NULL) */ new_cb = (struct side_callback *) calloc(old_nr_cb + 2, sizeof(struct side_callback)); if (!new_cb) { @@ -140,47 +167,47 @@ int _side_tracer_callback_register(struct side_event_description *desc, } memcpy(new_cb, old_cb, old_nr_cb); if (desc->flags & SIDE_EVENT_FLAG_VARIADIC) - new_cb[old_nr_cb].u.call_variadic = call; + new_cb[old_nr_cb].u.call_variadic = + (side_tracer_callback_variadic_func) call; else - new_cb[old_nr_cb].u.call = call; + new_cb[old_nr_cb].u.call = + (side_tracer_callback_func) call; new_cb[old_nr_cb].priv = priv; - side_rcu_assign_pointer(desc->callbacks, new_cb); + side_rcu_assign_pointer(event_state->callbacks, new_cb); side_rcu_wait_grace_period(&rcu_gp); if (old_nr_cb) free(old_cb); + desc->nr_callbacks++; /* Increment concurrently with kernel setting the top bits. */ - (void) __atomic_add_fetch(desc->enabled, 1, __ATOMIC_RELAXED); + if (!old_nr_cb) + (void) __atomic_add_fetch(&event_state->enabled, 1, __ATOMIC_RELAXED); unlock: pthread_mutex_unlock(&side_lock); return ret; } int side_tracer_callback_register(struct side_event_description *desc, - void (*call)(const struct side_event_description *desc, - const struct side_arg_vec_description *sav_desc, - void *priv), + side_tracer_callback_func call, void *priv) { if (desc->flags & SIDE_EVENT_FLAG_VARIADIC) return SIDE_ERROR_INVAL; - return _side_tracer_callback_register(desc, call, priv); + return _side_tracer_callback_register(desc, (void *) call, priv); } int side_tracer_callback_variadic_register(struct side_event_description *desc, - void (*call_variadic)(const struct side_event_description *desc, - const struct side_arg_vec_description *sav_desc, - const struct side_arg_dynamic_event_struct *var_struct, - void *priv), + side_tracer_callback_variadic_func call_variadic, void *priv) { if (!(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) return SIDE_ERROR_INVAL; - return _side_tracer_callback_register(desc, call_variadic, priv); + return _side_tracer_callback_register(desc, (void *) call_variadic, priv); } -int _side_tracer_callback_unregister(struct side_event_description *desc, - void (*call)(), void *priv) +static int _side_tracer_callback_unregister(struct side_event_description *desc, + void *call, void *priv) { + struct side_event_state *event_state; struct side_callback *old_cb, *new_cb; const struct side_callback *cb_pos; uint32_t pos_idx; @@ -189,18 +216,23 @@ int _side_tracer_callback_unregister(struct side_event_description *desc, if (!call) return SIDE_ERROR_INVAL; + if (finalized) + return SIDE_ERROR_EXITING; + if (!initialized) + side_init(); pthread_mutex_lock(&side_lock); + event_state = side_ptr_get(desc->state); cb_pos = side_tracer_callback_lookup(desc, call, priv); if (!cb_pos) { ret = SIDE_ERROR_NOENT; goto unlock; } - old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK; - old_cb = (struct side_callback *) desc->callbacks; + old_nr_cb = desc->nr_callbacks; + old_cb = (struct side_callback *) event_state->callbacks; if (old_nr_cb == 1) { new_cb = (struct side_callback *) &side_empty_callback; } else { - pos_idx = cb_pos - desc->callbacks; + pos_idx = cb_pos - event_state->callbacks; /* Remove entry at pos_idx. */ /* old_nr_cb - 1 (removed cb) + 1 (NULL) */ new_cb = (struct side_callback *) calloc(old_nr_cb, sizeof(struct side_callback)); @@ -211,40 +243,170 @@ int _side_tracer_callback_unregister(struct side_event_description *desc, memcpy(new_cb, old_cb, pos_idx); memcpy(&new_cb[pos_idx], &old_cb[pos_idx + 1], old_nr_cb - pos_idx - 1); } - side_rcu_assign_pointer(desc->callbacks, new_cb); + side_rcu_assign_pointer(event_state->callbacks, new_cb); side_rcu_wait_grace_period(&rcu_gp); free(old_cb); + desc->nr_callbacks--; /* Decrement concurrently with kernel setting the top bits. */ - (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED); + if (old_nr_cb == 1) + (void) __atomic_add_fetch(&event_state->enabled, -1, __ATOMIC_RELAXED); unlock: pthread_mutex_unlock(&side_lock); return ret; } int side_tracer_callback_unregister(struct side_event_description *desc, - void (*call)(const struct side_event_description *desc, - const struct side_arg_vec_description *sav_desc, - void *priv), + side_tracer_callback_func call, void *priv) { if (desc->flags & SIDE_EVENT_FLAG_VARIADIC) return SIDE_ERROR_INVAL; - return _side_tracer_callback_unregister(desc, call, priv); + return _side_tracer_callback_unregister(desc, (void *) call, priv); } int side_tracer_callback_variadic_unregister(struct side_event_description *desc, - void (*call_variadic)(const struct side_event_description *desc, - const struct side_arg_vec_description *sav_desc, - const struct side_arg_dynamic_event_struct *var_struct, - void *priv), + side_tracer_callback_variadic_func call_variadic, void *priv) { if (!(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) return SIDE_ERROR_INVAL; - return _side_tracer_callback_unregister(desc, call_variadic, priv); + return _side_tracer_callback_unregister(desc, (void *) call_variadic, priv); +} + +struct side_events_register_handle *side_events_register(struct side_event_description **events, uint32_t nr_events) +{ + struct side_events_register_handle *events_handle = NULL; + struct side_tracer_handle *tracer_handle; + + if (finalized) + return NULL; + if (!initialized) + side_init(); + events_handle = (struct side_events_register_handle *) + calloc(1, sizeof(struct side_events_register_handle)); + if (!events_handle) + return NULL; + events_handle->events = events; + events_handle->nr_events = nr_events; + + pthread_mutex_lock(&side_lock); + side_list_insert_node_tail(&side_events_list, &events_handle->node); + side_list_for_each_entry(tracer_handle, &side_tracer_list, node) { + tracer_handle->cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS, + events, nr_events, tracer_handle->priv); + } + pthread_mutex_unlock(&side_lock); + //TODO: call event batch register ioctl + return events_handle; } static +void side_event_remove_callbacks(struct side_event_description *desc) +{ + struct side_event_state *event_state = side_ptr_get(desc->state); + uint32_t nr_cb = desc->nr_callbacks; + struct side_callback *old_cb; + + if (!nr_cb) + return; + old_cb = (struct side_callback *) event_state->callbacks; + (void) __atomic_add_fetch(&event_state->enabled, -1, __ATOMIC_RELAXED); + /* + * Setting the state back to 0 cb and empty callbacks out of + * caution. This should not matter because instrumentation is + * unreachable. + */ + desc->nr_callbacks = 0; + side_rcu_assign_pointer(event_state->callbacks, &side_empty_callback); + /* + * No need to wait for grace period because instrumentation is + * unreachable. + */ + free(old_cb); +} + +/* + * Unregister event handle. At this point, all side events in that + * handle should be unreachable. + */ +void side_events_unregister(struct side_events_register_handle *events_handle) +{ + struct side_tracer_handle *tracer_handle; + uint32_t i; + + if (!events_handle) + return; + if (finalized) + return; + if (!initialized) + side_init(); + pthread_mutex_lock(&side_lock); + side_list_remove_node(&events_handle->node); + side_list_for_each_entry(tracer_handle, &side_tracer_list, node) { + tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS, + events_handle->events, events_handle->nr_events, + tracer_handle->priv); + } + for (i = 0; i < events_handle->nr_events; i++) { + struct side_event_description *event = events_handle->events[i]; + + /* Skip NULL pointers */ + if (!event) + continue; + side_event_remove_callbacks(event); + } + pthread_mutex_unlock(&side_lock); + //TODO: call event batch unregister ioctl + free(events_handle); +} + +struct side_tracer_handle *side_tracer_event_notification_register( + void (*cb)(enum side_tracer_notification notif, + struct side_event_description **events, uint32_t nr_events, void *priv), + void *priv) +{ + struct side_tracer_handle *tracer_handle; + struct side_events_register_handle *events_handle; + + if (finalized) + return NULL; + if (!initialized) + side_init(); + tracer_handle = (struct side_tracer_handle *) + calloc(1, sizeof(struct side_tracer_handle)); + if (!tracer_handle) + return NULL; + pthread_mutex_lock(&side_lock); + tracer_handle->cb = cb; + tracer_handle->priv = priv; + side_list_insert_node_tail(&side_tracer_list, &tracer_handle->node); + side_list_for_each_entry(events_handle, &side_events_list, node) { + cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS, + events_handle->events, events_handle->nr_events, priv); + } + pthread_mutex_unlock(&side_lock); + return tracer_handle; +} + +void side_tracer_event_notification_unregister(struct side_tracer_handle *tracer_handle) +{ + struct side_events_register_handle *events_handle; + + if (finalized) + return; + if (!initialized) + side_init(); + pthread_mutex_lock(&side_lock); + side_list_for_each_entry(events_handle, &side_events_list, node) { + tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS, + events_handle->events, events_handle->nr_events, + tracer_handle->priv); + } + side_list_remove_node(&tracer_handle->node); + pthread_mutex_unlock(&side_lock); + free(tracer_handle); +} + void side_init(void) { if (initialized) @@ -252,3 +414,20 @@ void side_init(void) side_rcu_gp_init(&rcu_gp); initialized = true; } + +/* + * side_exit() is executed from a library destructor. It can be called + * explicitly at application exit as well. Concurrent side API use is + * not expected at that point. + */ +void side_exit(void) +{ + struct side_events_register_handle *handle, *tmp; + + if (finalized) + return; + side_list_for_each_entry_safe(handle, tmp, &side_events_list, node) + side_events_unregister(handle); + side_rcu_gp_exit(&rcu_gp); + finalized = true; +}