+++ /dev/null
-/*
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
- * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#include <stddef.h>
-#include <stdlib.h>
-#include <urcu.h>
-#include <common/futex.h>
-#include <common/macros.h>
-
-#include "dispatch.h"
-#include "ust-app.h"
-#include "testpoint.h"
-#include "fd-limit.h"
-#include "health-sessiond.h"
-#include "lttng-sessiond.h"
-#include "thread.h"
-
-struct thread_notifiers {
- struct ust_cmd_queue *ust_cmd_queue;
- int apps_cmd_pipe_write_fd;
- int apps_cmd_notify_pipe_write_fd;
- int dispatch_thread_exit;
-};
-
-/*
- * For each tracing session, update newly registered apps. The session list
- * lock MUST be acquired before calling this.
- */
-static void update_ust_app(int app_sock)
-{
- struct ltt_session *sess, *stmp;
- const struct ltt_session_list *session_list = session_get_list();
- struct ust_app *app;
-
- /* Consumer is in an ERROR state. Stop any application update. */
- if (uatomic_read(&the_ust_consumerd_state) == CONSUMER_ERROR) {
- /* Stop the update process since the consumer is dead. */
- return;
- }
-
- rcu_read_lock();
- LTTNG_ASSERT(app_sock >= 0);
- app = ust_app_find_by_sock(app_sock);
- if (app == NULL) {
- /*
- * Application can be unregistered before so
- * this is possible hence simply stopping the
- * update.
- */
- DBG3("UST app update failed to find app sock %d",
- app_sock);
- goto unlock_rcu;
- }
-
- /* Update all event notifiers for the app. */
- ust_app_global_update_event_notifier_rules(app);
-
- /* For all tracing session(s) */
- cds_list_for_each_entry_safe(sess, stmp, &session_list->head, list) {
- if (!session_get(sess)) {
- continue;
- }
- session_lock(sess);
- if (!sess->active || !sess->ust_session ||
- !sess->ust_session->active) {
- goto unlock_session;
- }
-
- ust_app_global_update(sess->ust_session, app);
- unlock_session:
- session_unlock(sess);
- session_put(sess);
- }
-
-unlock_rcu:
- rcu_read_unlock();
-}
-
-/*
- * Sanitize the wait queue of the dispatch registration thread meaning removing
- * invalid nodes from it. This is to avoid memory leaks for the case the UST
- * notify socket is never received.
- */
-static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
-{
- int ret, nb_fd = 0, i;
- unsigned int fd_added = 0;
- struct lttng_poll_event events;
- struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node;
-
- LTTNG_ASSERT(wait_queue);
-
- lttng_poll_init(&events);
-
- /* Just skip everything for an empty queue. */
- if (!wait_queue->count) {
- goto end;
- }
-
- ret = lttng_poll_create(&events, wait_queue->count, LTTNG_CLOEXEC);
- if (ret < 0) {
- goto error_create;
- }
-
- cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
- &wait_queue->head, head) {
- LTTNG_ASSERT(wait_node->app);
- ret = lttng_poll_add(&events, wait_node->app->sock,
- LPOLLHUP | LPOLLERR);
- if (ret < 0) {
- goto error;
- }
-
- fd_added = 1;
- }
-
- if (!fd_added) {
- goto end;
- }
-
- /*
- * Poll but don't block so we can quickly identify the faulty events and
- * clean them afterwards from the wait queue.
- */
- ret = lttng_poll_wait(&events, 0);
- if (ret < 0) {
- goto error;
- }
- nb_fd = ret;
-
- for (i = 0; i < nb_fd; i++) {
- /* Get faulty FD. */
- uint32_t revents = LTTNG_POLL_GETEV(&events, i);
- int pollfd = LTTNG_POLL_GETFD(&events, i);
-
- cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
- &wait_queue->head, head) {
- if (pollfd == wait_node->app->sock &&
- (revents & (LPOLLHUP | LPOLLERR))) {
- cds_list_del(&wait_node->head);
- wait_queue->count--;
- ust_app_destroy(wait_node->app);
- free(wait_node);
- /*
- * Silence warning of use-after-free in
- * cds_list_for_each_entry_safe which uses
- * __typeof__(*wait_node).
- */
- wait_node = NULL;
- break;
- } else {
- ERR("Unexpected poll events %u for sock %d", revents, pollfd);
- goto error;
- }
- }
- }
-
- if (nb_fd > 0) {
- DBG("Wait queue sanitized, %d node were cleaned up", nb_fd);
- }
-
-end:
- lttng_poll_clean(&events);
- return;
-
-error:
- lttng_poll_clean(&events);
-error_create:
- ERR("Unable to sanitize wait queue");
- return;
-}
-
-/*
- * Send a socket to a thread This is called from the dispatch UST registration
- * thread once all sockets are set for the application.
- *
- * The sock value can be invalid, we don't really care, the thread will handle
- * it and make the necessary cleanup if so.
- *
- * On success, return 0 else a negative value being the errno message of the
- * write().
- */
-static int send_socket_to_thread(int fd, int sock)
-{
- ssize_t ret;
-
- /*
- * It's possible that the FD is set as invalid with -1 concurrently just
- * before calling this function being a shutdown state of the thread.
- */
- if (fd < 0) {
- ret = -EBADF;
- goto error;
- }
-
- ret = lttng_write(fd, &sock, sizeof(sock));
- if (ret < sizeof(sock)) {
- PERROR("write apps pipe %d", fd);
- if (ret < 0) {
- ret = -errno;
- }
- goto error;
- }
-
- /* All good. Don't send back the write positive ret value. */
- ret = 0;
-error:
- return (int) ret;
-}
-
-static void cleanup_ust_dispatch_thread(void *data)
-{
- free(data);
-}
-
-/*
- * Dispatch request from the registration threads to the application
- * communication thread.
- */
-static void *thread_dispatch_ust_registration(void *data)
-{
- int ret, err = -1;
- struct cds_wfcq_node *node;
- struct ust_command *ust_cmd = NULL;
- struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node;
- struct ust_reg_wait_queue wait_queue = {
- .count = 0,
- };
- struct thread_notifiers *notifiers = data;
-
- rcu_register_thread();
-
- health_register(the_health_sessiond,
- HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH);
-
- if (testpoint(sessiond_thread_app_reg_dispatch)) {
- goto error_testpoint;
- }
-
- health_code_update();
-
- CDS_INIT_LIST_HEAD(&wait_queue.head);
-
- DBG("[thread] Dispatch UST command started");
-
- for (;;) {
- health_code_update();
-
- /* Atomically prepare the queue futex */
- futex_nto1_prepare(¬ifiers->ust_cmd_queue->futex);
-
- if (CMM_LOAD_SHARED(notifiers->dispatch_thread_exit)) {
- break;
- }
-
- do {
- struct ust_app *app = NULL;
- ust_cmd = NULL;
-
- /*
- * Make sure we don't have node(s) that have hung up before receiving
- * the notify socket. This is to clean the list in order to avoid
- * memory leaks from notify socket that are never seen.
- */
- sanitize_wait_queue(&wait_queue);
-
- health_code_update();
- /* Dequeue command for registration */
- node = cds_wfcq_dequeue_blocking(
- ¬ifiers->ust_cmd_queue->head,
- ¬ifiers->ust_cmd_queue->tail);
- if (node == NULL) {
- DBG("Woken up but nothing in the UST command queue");
- /* Continue thread execution */
- break;
- }
-
- ust_cmd = caa_container_of(node, struct ust_command, node);
-
- DBG("Dispatching UST registration pid:%d ppid:%d uid:%d"
- " gid:%d sock:%d name:%s (version %d.%d)",
- ust_cmd->reg_msg.pid, ust_cmd->reg_msg.ppid,
- ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid,
- ust_cmd->sock, ust_cmd->reg_msg.name,
- ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor);
-
- if (ust_cmd->reg_msg.type == LTTNG_UST_CTL_SOCKET_CMD) {
- wait_node = zmalloc(sizeof(*wait_node));
- if (!wait_node) {
- PERROR("zmalloc wait_node dispatch");
- ret = close(ust_cmd->sock);
- if (ret < 0) {
- PERROR("close ust sock dispatch %d", ust_cmd->sock);
- }
- lttng_fd_put(LTTNG_FD_APPS, 1);
- free(ust_cmd);
- ust_cmd = NULL;
- goto error;
- }
- CDS_INIT_LIST_HEAD(&wait_node->head);
-
- /* Create application object if socket is CMD. */
- wait_node->app = ust_app_create(&ust_cmd->reg_msg,
- ust_cmd->sock);
- if (!wait_node->app) {
- ret = close(ust_cmd->sock);
- if (ret < 0) {
- PERROR("close ust sock dispatch %d", ust_cmd->sock);
- }
- lttng_fd_put(LTTNG_FD_APPS, 1);
- free(wait_node);
- wait_node = NULL;
- free(ust_cmd);
- ust_cmd = NULL;
- continue;
- }
- /*
- * Add application to the wait queue so we can set the notify
- * socket before putting this object in the global ht.
- */
- cds_list_add(&wait_node->head, &wait_queue.head);
- wait_queue.count++;
-
- free(ust_cmd);
- ust_cmd = NULL;
- /*
- * We have to continue here since we don't have the notify
- * socket and the application MUST be added to the hash table
- * only at that moment.
- */
- continue;
- } else {
- /*
- * Look for the application in the local wait queue and set the
- * notify socket if found.
- */
- cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
- &wait_queue.head, head) {
- health_code_update();
- if (wait_node->app->pid == ust_cmd->reg_msg.pid) {
- wait_node->app->notify_sock = ust_cmd->sock;
- cds_list_del(&wait_node->head);
- wait_queue.count--;
- app = wait_node->app;
- free(wait_node);
- wait_node = NULL;
- DBG3("UST app notify socket %d is set", ust_cmd->sock);
- break;
- }
- }
-
- /*
- * With no application at this stage the received socket is
- * basically useless so close it before we free the cmd data
- * structure for good.
- */
- if (!app) {
- ret = close(ust_cmd->sock);
- if (ret < 0) {
- PERROR("close ust sock dispatch %d", ust_cmd->sock);
- }
- lttng_fd_put(LTTNG_FD_APPS, 1);
- }
- free(ust_cmd);
- ust_cmd = NULL;
- }
-
- if (app) {
- /*
- * @session_lock_list
- *
- * Lock the global session list so from the register up to the
- * registration done message, no thread can see the application
- * and change its state.
- */
- session_lock_list();
- rcu_read_lock();
-
- /*
- * Add application to the global hash table. This needs to be
- * done before the update to the UST registry can locate the
- * application.
- */
- ust_app_add(app);
-
- /* Set app version. This call will print an error if needed. */
- (void) ust_app_version(app);
-
- (void) ust_app_setup_event_notifier_group(app);
-
- /* Send notify socket through the notify pipe. */
- ret = send_socket_to_thread(
- notifiers->apps_cmd_notify_pipe_write_fd,
- app->notify_sock);
- if (ret < 0) {
- rcu_read_unlock();
- session_unlock_list();
- /*
- * No notify thread, stop the UST tracing. However, this is
- * not an internal error of the this thread thus setting
- * the health error code to a normal exit.
- */
- err = 0;
- goto error;
- }
-
- /*
- * Update newly registered application with the tracing
- * registry info already enabled information.
- */
- update_ust_app(app->sock);
-
- /*
- * Don't care about return value. Let the manage apps threads
- * handle app unregistration upon socket close.
- */
- (void) ust_app_register_done(app);
-
- /*
- * Even if the application socket has been closed, send the app
- * to the thread and unregistration will take place at that
- * place.
- */
- ret = send_socket_to_thread(
- notifiers->apps_cmd_pipe_write_fd,
- app->sock);
- if (ret < 0) {
- rcu_read_unlock();
- session_unlock_list();
- /*
- * No apps. thread, stop the UST tracing. However, this is
- * not an internal error of the this thread thus setting
- * the health error code to a normal exit.
- */
- err = 0;
- goto error;
- }
-
- rcu_read_unlock();
- session_unlock_list();
- }
- } while (node != NULL);
-
- health_poll_entry();
- /* Futex wait on queue. Blocking call on futex() */
- futex_nto1_wait(¬ifiers->ust_cmd_queue->futex);
- health_poll_exit();
- }
- /* Normal exit, no error */
- err = 0;
-
-error:
- /* Clean up wait queue. */
- cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
- &wait_queue.head, head) {
- cds_list_del(&wait_node->head);
- wait_queue.count--;
- free(wait_node);
- }
-
- /* Empty command queue. */
- for (;;) {
- /* Dequeue command for registration */
- node = cds_wfcq_dequeue_blocking(
- ¬ifiers->ust_cmd_queue->head,
- ¬ifiers->ust_cmd_queue->tail);
- if (node == NULL) {
- break;
- }
- ust_cmd = caa_container_of(node, struct ust_command, node);
- ret = close(ust_cmd->sock);
- if (ret < 0) {
- PERROR("close ust sock exit dispatch %d", ust_cmd->sock);
- }
- lttng_fd_put(LTTNG_FD_APPS, 1);
- free(ust_cmd);
- }
-
-error_testpoint:
- DBG("Dispatch thread dying");
- if (err) {
- health_error();
- ERR("Health error occurred in %s", __func__);
- }
- health_unregister(the_health_sessiond);
- rcu_unregister_thread();
- return NULL;
-}
-
-static bool shutdown_ust_dispatch_thread(void *data)
-{
- struct thread_notifiers *notifiers = data;
-
- CMM_STORE_SHARED(notifiers->dispatch_thread_exit, 1);
- futex_nto1_wake(¬ifiers->ust_cmd_queue->futex);
- return true;
-}
-
-bool launch_ust_dispatch_thread(struct ust_cmd_queue *cmd_queue,
- int apps_cmd_pipe_write_fd,
- int apps_cmd_notify_pipe_write_fd)
-{
- struct lttng_thread *thread;
- struct thread_notifiers *notifiers;
-
- notifiers = zmalloc(sizeof(*notifiers));
- if (!notifiers) {
- goto error;
- }
- notifiers->ust_cmd_queue = cmd_queue;
- notifiers->apps_cmd_pipe_write_fd = apps_cmd_pipe_write_fd;
- notifiers->apps_cmd_notify_pipe_write_fd = apps_cmd_notify_pipe_write_fd;
-
- thread = lttng_thread_create("UST registration dispatch",
- thread_dispatch_ust_registration,
- shutdown_ust_dispatch_thread,
- cleanup_ust_dispatch_thread,
- notifiers);
- if (!thread) {
- goto error;
- }
- lttng_thread_put(thread);
- return true;
-error:
- free(notifiers);
- return false;
-}
projects / lttng-tools.git / blobdiff