From: Jonathan Rajotte Date: Tue, 31 Mar 2020 18:33:18 +0000 (-0400) Subject: sessiond: notification: receive incoming notifications from tracers X-Git-Tag: v2.13.0-rc1~364 X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=940786035bcaf18b6b19a6a98f928ad4f52375f4 sessiond: notification: receive incoming notifications from tracers Receive and discard notifications received by tracers. This simply puts in place the basic tracer notification reception mechanisms. Signed-off-by: Jonathan Rajotte Signed-off-by: Jérémie Galarneau Change-Id: I3d94431051015c69785ec256095135746e3972ce --- diff --git a/src/bin/lttng-sessiond/notification-thread-events.c b/src/bin/lttng-sessiond/notification-thread-events.c index 1a71131f0..d62015924 100644 --- a/src/bin/lttng-sessiond/notification-thread-events.c +++ b/src/bin/lttng-sessiond/notification-thread-events.c @@ -125,6 +125,19 @@ struct lttng_condition_list_element { struct cds_list_head node; }; +/* + * Facilities to carry the different notifications type in the action processing + * code path. + */ +struct lttng_event_notifier_notification { + union { + struct lttng_ust_event_notifier_notification *ust; + struct lttng_kernel_event_notifier_notification *kernel; + } notification; + uint64_t token; + enum lttng_domain_type type; +}; + struct channel_state_sample { struct channel_key key; struct cds_lfht_node channel_state_ht_node; @@ -4133,6 +4146,99 @@ end: return ret; } +int handle_notification_thread_event_notification(struct notification_thread_state *state, + int notification_pipe_read_fd, + enum lttng_domain_type domain) +{ + int ret; + struct lttng_ust_event_notifier_notification ust_notification; + struct lttng_kernel_event_notifier_notification kernel_notification; + struct cds_lfht_node *node; + struct cds_lfht_iter iter; + struct notification_trigger_tokens_ht_element *element; + enum lttng_action_type action_type; + const struct lttng_action *action; + struct lttng_event_notifier_notification notification; + void *reception_buffer; + size_t reception_size; + + notification.type = domain; + + switch(domain) { + case LTTNG_DOMAIN_UST: + reception_buffer = (void *) &ust_notification; + reception_size = sizeof(ust_notification); + notification.notification.ust = &ust_notification; + break; + case LTTNG_DOMAIN_KERNEL: + reception_buffer = (void *) &kernel_notification; + reception_size = sizeof(kernel_notification); + notification.notification.kernel = &kernel_notification; + break; + default: + abort(); + } + + /* + * The monitoring pipe only holds messages smaller than PIPE_BUF, + * ensuring that read/write of tracer notifications are atomic. + */ + ret = lttng_read(notification_pipe_read_fd, reception_buffer, + reception_size); + if (ret != reception_size) { + PERROR("Failed to read from event source notification pipe: fd = %d, size to read = %zu, ret = %d", + notification_pipe_read_fd, reception_size, ret); + ret = -1; + goto end; + } + + switch(domain) { + case LTTNG_DOMAIN_UST: + notification.token = ust_notification.token; + break; + case LTTNG_DOMAIN_KERNEL: + notification.token = kernel_notification.token; + break; + default: + abort(); + } + + /* Find triggers associated with this token. */ + rcu_read_lock(); + cds_lfht_lookup(state->trigger_tokens_ht, + hash_key_u64(¬ification.token, lttng_ht_seed), + match_trigger_token, ¬ification.token, &iter); + node = cds_lfht_iter_get_node(&iter); + if (caa_likely(!node)) { + /* + * This is not an error, slow consumption of the pipe can lead + * to situations where a trigger is removed but we still get + * tracer notification matching to a previous trigger. + */ + ret = 0; + goto end_unlock; + } + + element = caa_container_of(node, + struct notification_trigger_tokens_ht_element, + node); + + action = lttng_trigger_get_const_action(element->trigger); + action_type = lttng_action_get_type(action); + DBG("Received message from tracer event source: event source fd = %d, token = %" PRIu64 ", action type = '%s'", + notification_pipe_read_fd, notification.token, + lttng_action_type_string(action_type)); + + /* TODO: Perform actions */ + + ret = 0; + +end_unlock: + rcu_read_unlock(); +end: + return ret; +} + int handle_notification_thread_channel_sample( struct notification_thread_state *state, int pipe, enum lttng_domain_type domain) diff --git a/src/bin/lttng-sessiond/notification-thread-events.h b/src/bin/lttng-sessiond/notification-thread-events.h index 3602f8dca..dffd26773 100644 --- a/src/bin/lttng-sessiond/notification-thread-events.h +++ b/src/bin/lttng-sessiond/notification-thread-events.h @@ -48,4 +48,8 @@ int handle_notification_thread_channel_sample( struct notification_thread_state *state, int pipe, enum lttng_domain_type domain); +int handle_notification_thread_event_notification( + struct notification_thread_state *state, int pipe, + enum lttng_domain_type domain); + #endif /* NOTIFICATION_THREAD_EVENTS_H */ diff --git a/src/bin/lttng-sessiond/notification-thread.c b/src/bin/lttng-sessiond/notification-thread.c index 1a7a16119..1ba724337 100644 --- a/src/bin/lttng-sessiond/notification-thread.c +++ b/src/bin/lttng-sessiond/notification-thread.c @@ -28,6 +28,9 @@ #include "health-sessiond.h" #include "thread.h" +#include "kernel.h" +#include + #include #include #include @@ -69,6 +72,7 @@ void notification_thread_handle_destroy( PERROR("close kernel consumer channel monitoring pipe"); } } + end: free(handle); } @@ -550,6 +554,59 @@ end: return ret; } +static int handle_event_notification_pipe(int event_source_fd, + enum lttng_domain_type domain, + uint32_t revents, + struct notification_thread_state *state) +{ + int ret = 0; + + if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) { + ret = handle_notification_thread_remove_tracer_event_source_no_result( + state, event_source_fd); + if (ret) { + ERR("[notification-thread] Failed to remove event notification pipe from poll set: fd = %d", + event_source_fd); + } + goto end; + } + + ret = handle_notification_thread_event_notification( + state, event_source_fd, domain); + if (ret) { + ERR("[notification-thread] Event notification handling error occurred for fd: %d", + event_source_fd); + ret = -1; + goto end; + } +end: + return ret; +} + +/* + * Return the event source domain type via parameter. + */ +static bool fd_is_event_notification_source(const struct notification_thread_state *state, + int fd, + enum lttng_domain_type *domain) +{ + struct notification_event_tracer_event_source_element *source_element; + + assert(domain); + + cds_list_for_each_entry(source_element, + &state->tracer_event_sources_list, node) { + if (source_element->fd != fd) { + continue; + } + + *domain = source_element->domain; + return true; + } + + return false; +} + /* * This thread services notification channel clients and commands received * from various lttng-sessiond components over a command queue. @@ -560,6 +617,7 @@ void *thread_notification(void *data) int ret; struct notification_thread_handle *handle = data; struct notification_thread_state state; + enum lttng_domain_type domain; DBG("[notification-thread] Started notification thread"); @@ -637,6 +695,11 @@ void *thread_notification(void *data) if (ret) { goto error; } + } else if (fd_is_event_notification_source(&state, fd, &domain)) { + ret = handle_event_notification_pipe(fd, domain, revents, &state); + if (ret) { + goto error; + } } else { /* Activity on a client's socket. */ if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {