X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=src%2Fside.c;h=43d342e26c1e54683502837b3726e5ffe5226ea2;hb=873bbf16c6bcfe2c11fca7e76dd7284c5afbee99;hp=14788d79d83ef855b77c4e268989a6802bf8b8c1;hpb=a3f36db71deaf74d9bae872ce1ec411145db7351;p=libside.git diff --git a/src/side.c b/src/side.c index 14788d7..43d342e 100644 --- a/src/side.c +++ b/src/side.c @@ -5,95 +5,192 @@ #include #include +#include -#include "tracer.h" #include "rcu.h" +#include "list.h" +#include "rculist.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 -static struct side_rcu_gp_state rcu_gp; +/* 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; +}; + +struct side_statedump_request_handle { + struct side_list_node node; /* RCU list. */ + void (*cb)(void); +}; + +struct side_callback { + union { + void (*call)(const struct side_event_description *desc, + const struct side_arg_vec *side_arg_vec, + void *priv); + void (*call_variadic)(const struct side_event_description *desc, + const struct side_arg_vec *side_arg_vec, + const struct side_arg_dynamic_struct *var_struct, + void *priv); + } u; + void *priv; + void *key; +}; + +static struct side_rcu_gp_state event_rcu_gp, statedump_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; +/* + * Recursive mutex to allow tracer callbacks to use the side API. + */ +static pthread_mutex_t side_event_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; +static pthread_mutex_t side_statedump_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); +static DEFINE_SIDE_LIST_HEAD(side_statedump_list); + +/* + * Callback filter key for state dump. + */ +static __thread void *filter_key; /* * 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 char side_empty_callback[sizeof(struct side_callback)]; -void side_call(const struct side_event_description *desc, const struct side_arg_vec_description *sav_desc) +static +void _side_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec, void *key) { + struct side_rcu_read_state rcu_read_state; + const struct side_event_state_0 *es0; const struct side_callback *side_cb; - unsigned int rcu_period; + 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"); + if (side_unlikely(event_state->version != 0)) abort(); - } - if (side_unlikely(*desc->enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) { + es0 = side_container_of(event_state, const struct side_event_state_0, parent); + assert(!(es0->desc->flags & SIDE_EVENT_FLAG_VARIADIC)); + enabled = __atomic_load_n(&es0->enabled, __ATOMIC_RELAXED); + if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) { // TODO: call kernel write. } - if (side_unlikely(!(*desc->enabled & SIDE_EVENT_ENABLED_USER_MASK))) - return; + side_rcu_read_begin(&event_rcu_gp, &rcu_read_state); + for (side_cb = side_rcu_dereference(es0->callbacks); side_cb->u.call != NULL; side_cb++) { + /* A NULL key is always a match. */ + if (key && side_cb->key && side_cb->key != key) + continue; + side_cb->u.call(es0->desc, side_arg_vec, side_cb->priv); + } + side_rcu_read_end(&event_rcu_gp, &rcu_read_state); +} - //TODO: replace tracer_call by rcu iteration on list of registered callbacks - tracer_call(desc, sav_desc, NULL); +void side_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec) +{ + _side_call(event_state, side_arg_vec, 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); +void side_statedump_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec) +{ + _side_call(event_state, side_arg_vec, filter_key); } -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) +static +void _side_call_variadic(const struct side_event_state *event_state, + const struct side_arg_vec *side_arg_vec, + const struct side_arg_dynamic_struct *var_struct, + void *key) { + struct side_rcu_read_state rcu_read_state; + const struct side_event_state_0 *es0; const struct side_callback *side_cb; - unsigned int rcu_period; + uintptr_t enabled; + if (side_unlikely(finalized)) + return; if (side_unlikely(!initialized)) side_init(); - if (side_unlikely(*desc->enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) { + if (side_unlikely(event_state->version != 0)) + abort(); + es0 = side_container_of(event_state, const struct side_event_state_0, parent); + assert(es0->desc->flags & SIDE_EVENT_FLAG_VARIADIC); + enabled = __atomic_load_n(&es0->enabled, __ATOMIC_RELAXED); + if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) { // TODO: call kernel write. } - if (side_unlikely(!(*desc->enabled & SIDE_EVENT_ENABLED_USER_MASK))) - return; + side_rcu_read_begin(&event_rcu_gp, &rcu_read_state); + for (side_cb = side_rcu_dereference(es0->callbacks); side_cb->u.call_variadic != NULL; side_cb++) { + /* A NULL key is always a match. */ + if (key && side_cb->key && side_cb->key != key) + continue; + side_cb->u.call_variadic(es0->desc, side_arg_vec, var_struct, side_cb->priv); + } + side_rcu_read_end(&event_rcu_gp, &rcu_read_state); +} - //TODO: replace tracer_call by rcu iteration on list of registered callbacks - tracer_call_variadic(desc, sav_desc, var_struct, NULL); +void side_call_variadic(const struct side_event_state *event_state, + const struct side_arg_vec *side_arg_vec, + const struct side_arg_dynamic_struct *var_struct) +{ + _side_call_variadic(event_state, side_arg_vec, 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); +void side_statedump_call_variadic(const struct side_event_state *event_state, + const struct side_arg_vec *side_arg_vec, + const struct side_arg_dynamic_struct *var_struct) +{ + _side_call_variadic(event_state, side_arg_vec, var_struct, filter_key); } static const struct side_callback *side_tracer_callback_lookup( const struct side_event_description *desc, - void (*call)(), void *priv) + void *call, void *priv, void *key) { + struct side_event_state *event_state = side_ptr_get(desc->state); + const struct side_event_state_0 *es0; const struct side_callback *cb; - for (cb = desc->callbacks; cb->u.call != NULL; cb++) { - if (cb->u.call == call && cb->priv == priv) + if (side_unlikely(event_state->version != 0)) + abort(); + es0 = side_container_of(event_state, const struct side_event_state_0, parent); + for (cb = es0->callbacks; cb->u.call != NULL; cb++) { + if ((void *) cb->u.call == call && cb->priv == priv && cb->key == key) return cb; } return NULL; @@ -101,26 +198,36 @@ 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, void *key) { + struct side_event_state *event_state; struct side_callback *old_cb, *new_cb; + struct side_event_state_0 *es0; int ret = SIDE_ERROR_OK; uint32_t old_nr_cb; if (!call) return SIDE_ERROR_INVAL; - pthread_mutex_lock(&side_lock); - old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK; - if (old_nr_cb == SIDE_EVENT_ENABLED_USER_MASK) { + if (finalized) + return SIDE_ERROR_EXITING; + if (!initialized) + side_init(); + pthread_mutex_lock(&side_event_lock); + event_state = side_ptr_get(desc->state); + if (side_unlikely(event_state->version != 0)) + abort(); + es0 = side_container_of(event_state, struct side_event_state_0, parent); + old_nr_cb = es0->nr_callbacks; + if (old_nr_cb == UINT32_MAX) { ret = SIDE_ERROR_INVAL; goto unlock; } /* Reject duplicate (call, priv) tuples. */ - if (side_tracer_callback_lookup(desc, call, priv)) { + if (side_tracer_callback_lookup(desc, call, priv, key)) { ret = SIDE_ERROR_EXIST; goto unlock; } - old_cb = (struct side_callback *) desc->callbacks; + old_cb = (struct side_callback *) es0->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) { @@ -129,71 +236,78 @@ 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_wait_grace_period(&rcu_gp); + new_cb[old_nr_cb].key = key; + /* High order bits are already zeroed. */ + side_rcu_assign_pointer(es0->callbacks, new_cb); + side_rcu_wait_grace_period(&event_rcu_gp); if (old_nr_cb) free(old_cb); + es0->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(&es0->enabled, 1, __ATOMIC_RELAXED); unlock: - pthread_mutex_unlock(&side_lock); + pthread_mutex_unlock(&side_event_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), - void *priv) + side_tracer_callback_func call, + void *priv, void *key) { 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, key); } 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), - void *priv) + side_tracer_callback_variadic_func call_variadic, + void *priv, void *key) { 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, key); } -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, void *key) { + struct side_event_state *event_state; struct side_callback *old_cb, *new_cb; const struct side_callback *cb_pos; + struct side_event_state_0 *es0; uint32_t pos_idx; int ret = SIDE_ERROR_OK; uint32_t old_nr_cb; if (!call) return SIDE_ERROR_INVAL; - pthread_mutex_lock(&side_lock); - old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK; - if (old_nr_cb == 0) { - ret = SIDE_ERROR_INVAL; - goto unlock; - } - old_cb = (struct side_callback *) desc->callbacks; - cb_pos = side_tracer_callback_lookup(desc, call, priv); + if (finalized) + return SIDE_ERROR_EXITING; + if (!initialized) + side_init(); + pthread_mutex_lock(&side_event_lock); + event_state = side_ptr_get(desc->state); + if (side_unlikely(event_state->version != 0)) + abort(); + es0 = side_container_of(event_state, struct side_event_state_0, parent); + cb_pos = side_tracer_callback_lookup(desc, call, priv, key); if (!cb_pos) { ret = SIDE_ERROR_NOENT; goto unlock; } + old_nr_cb = es0->nr_callbacks; + old_cb = (struct side_callback *) es0->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 - es0->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)); @@ -204,44 +318,258 @@ 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_wait_grace_period(&rcu_gp); + /* High order bits are already zeroed. */ + side_rcu_assign_pointer(es0->callbacks, new_cb); + side_rcu_wait_grace_period(&event_rcu_gp); free(old_cb); + es0->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(&es0->enabled, -1, __ATOMIC_RELAXED); unlock: - pthread_mutex_unlock(&side_lock); + pthread_mutex_unlock(&side_event_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), - void *priv) + side_tracer_callback_func call, + void *priv, void *key) { 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, key); } 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), - void *priv) + side_tracer_callback_variadic_func call_variadic, + void *priv, void *key) { 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, key); +} + +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_event_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_event_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); + struct side_event_state_0 *es0; + struct side_callback *old_cb; + uint32_t nr_cb; + + if (side_unlikely(event_state->version != 0)) + abort(); + es0 = side_container_of(event_state, struct side_event_state_0, parent); + nr_cb = es0->nr_callbacks; + if (!nr_cb) + return; + old_cb = (struct side_callback *) es0->callbacks; + (void) __atomic_add_fetch(&es0->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. + */ + es0->nr_callbacks = 0; + side_rcu_assign_pointer(es0->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_event_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_event_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_event_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_event_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_event_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_event_lock); + free(tracer_handle); +} + +struct side_statedump_request_handle *side_statedump_request_notification_register(void (*statedump_cb)(void)) +{ + struct side_statedump_request_handle *handle; + + if (finalized) + return NULL; + if (!initialized) + side_init(); + /* + * The statedump request notification should not be registered + * from a notification callback. + */ + assert(filter_key == NULL); + handle = (struct side_statedump_request_handle *) + calloc(1, sizeof(struct side_statedump_request_handle)); + if (!handle) + return NULL; + handle->cb = statedump_cb; + + pthread_mutex_lock(&side_statedump_lock); + side_list_insert_node_tail_rcu(&side_statedump_list, &handle->node); + pthread_mutex_unlock(&side_statedump_lock); + + /* Invoke callback for all tracers. */ + statedump_cb(); + + return handle; +} + +void side_statedump_request_notification_unregister(struct side_statedump_request_handle *handle) +{ + if (finalized) + return; + if (!initialized) + side_init(); + assert(filter_key == NULL); + + pthread_mutex_lock(&side_statedump_lock); + side_list_remove_node_rcu(&handle->node); + pthread_mutex_unlock(&side_statedump_lock); + + side_rcu_wait_grace_period(&statedump_rcu_gp); + free(handle); +} + +void side_tracer_statedump_request(void *key) +{ + struct side_statedump_request_handle *handle; + struct side_rcu_read_state rcu_read_state; + + /* Invoke the state dump callback specifically for the tracer key. */ + filter_key = key; + side_rcu_read_begin(&statedump_rcu_gp, &rcu_read_state); + side_list_for_each_entry_rcu(handle, &side_statedump_list, node) + handle->cb(); + side_rcu_read_end(&statedump_rcu_gp, &rcu_read_state); + filter_key = NULL; +} + void side_init(void) { if (initialized) return; - side_rcu_gp_init(&rcu_gp); + side_rcu_gp_init(&event_rcu_gp); + side_rcu_gp_init(&statedump_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(&event_rcu_gp); + side_rcu_gp_exit(&statedump_rcu_gp); + finalized = true; +}