--- /dev/null
+/*
+ * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define _GNU_SOURCE
+#include <assert.h>
+
+#include <common/common.h>
+#include <common/sessiond-comm/sessiond-comm.h>
+#include <common/uri.h>
+#include <common/utils.h>
+
+#include "fd-limit.h"
+#include "jul-thread.h"
+#include "lttng-sessiond.h"
+#include "session.h"
+#include "utils.h"
+
+/*
+ * Note that there is not port here. It's set after this URI is parsed so we
+ * can let the user define a custom one. However, localhost is ALWAYS the
+ * default listening address.
+ */
+static const char *default_reg_uri = "tcp://localhost";
+
+/*
+ * Update JUL application using the given socket. This is done just after
+ * registration was successful.
+ *
+ * This is a quite heavy call in terms of locking since the session list lock
+ * AND session lock are acquired.
+ */
+static void update_jul_app(int sock)
+{
+ struct ltt_session *session, *stmp;
+ struct ltt_session_list *list;
+
+ list = session_get_list();
+ assert(list);
+
+ session_lock_list();
+ cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
+ session_lock(session);
+ if (session->ust_session) {
+ jul_update(&session->ust_session->domain_jul, sock);
+ }
+ session_unlock(session);
+ }
+ session_unlock_list();
+}
+
+/*
+ * Destroy a JUL application by socket.
+ */
+static void destroy_jul_app(int sock)
+{
+ struct jul_app *app;
+
+ assert(sock >= 0);
+
+ /*
+ * Not finding an application is a very important error that should NEVER
+ * happen. The hash table deletion is ONLY done through this call even on
+ * thread cleanup.
+ */
+ rcu_read_lock();
+ app = jul_find_app_by_sock(sock);
+ assert(app);
+ rcu_read_unlock();
+
+ /* RCU read side lock is taken in this function call. */
+ jul_delete_app(app);
+
+ /* The application is freed in a RCU call but the socket is closed here. */
+ jul_destroy_app(app);
+}
+
+/*
+ * Cleanup remaining JUL apps in the hash table. This should only be called in
+ * the exit path of the thread.
+ */
+static void clean_jul_apps_ht(void)
+{
+ struct lttng_ht_node_ulong *node;
+ struct lttng_ht_iter iter;
+
+ DBG3("[jul-thread] Cleaning JUL apps ht");
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry(jul_apps_ht_by_sock->ht, &iter.iter, node, node) {
+ struct jul_app *app;
+
+ app = caa_container_of(node, struct jul_app, node);
+ destroy_jul_app(app->sock->fd);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Create and init socket from uri.
+ */
+static struct lttcomm_sock *init_tcp_socket(void)
+{
+ int ret;
+ struct lttng_uri *uri = NULL;
+ struct lttcomm_sock *sock = NULL;
+
+ /*
+ * This should never fail since the URI is hardcoded and the port is set
+ * before this thread is launched.
+ */
+ ret = uri_parse(default_reg_uri, &uri);
+ assert(ret);
+ assert(jul_tcp_port);
+ uri->port = jul_tcp_port;
+
+ sock = lttcomm_alloc_sock_from_uri(uri);
+ uri_free(uri);
+ if (sock == NULL) {
+ ERR("[jul-thread] JUL allocating TCP socket");
+ goto error;
+ }
+
+ ret = lttcomm_create_sock(sock);
+ if (ret < 0) {
+ goto error;
+ }
+
+ ret = sock->ops->bind(sock);
+ if (ret < 0) {
+ goto error;
+ }
+
+ ret = sock->ops->listen(sock, -1);
+ if (ret < 0) {
+ goto error;
+ }
+
+ DBG("[jul-thread] Listening on TCP port %u and socket %d", jul_tcp_port,
+ sock->fd);
+
+ return sock;
+
+error:
+ if (sock) {
+ lttcomm_destroy_sock(sock);
+ }
+ return NULL;
+}
+
+/*
+ * Close and destroy the given TCP socket.
+ */
+static void destroy_tcp_socket(struct lttcomm_sock *sock)
+{
+ assert(sock);
+
+ DBG3("[jul-thread] Destroy TCP socket on port %u", jul_tcp_port);
+
+ /* This will return gracefully if fd is invalid. */
+ sock->ops->close(sock);
+ lttcomm_destroy_sock(sock);
+}
+
+/*
+ * Handle a new JUL registration using the reg socket. After that, a new JUL
+ * application is added to the global hash table and attach to an UST app
+ * object.
+ *
+ * Return the new FD created upon accept() on success or else a negative errno
+ * value.
+ */
+static int handle_registration(struct lttcomm_sock *reg_sock)
+{
+ int ret;
+ pid_t pid;
+ ssize_t size;
+ struct jul_app *app;
+ struct jul_register_msg msg;
+ struct lttcomm_sock *new_sock;
+
+ assert(reg_sock);
+
+ new_sock = reg_sock->ops->accept(reg_sock);
+ if (!new_sock) {
+ ret = -ENOTCONN;
+ goto error;
+ }
+
+ size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
+ if (size < sizeof(msg)) {
+ ret = -errno;
+ goto error_socket;
+ }
+ pid = be32toh(msg.pid);
+
+ DBG2("[jul-thread] New registration for pid %d on socket %d", pid,
+ new_sock->fd);
+
+ app = jul_create_app(pid, new_sock);
+ if (!app) {
+ ret = -ENOMEM;
+ goto error_socket;
+ }
+
+ /*
+ * Add before assigning the socket value to the UST app so it can be found
+ * concurrently.
+ */
+ jul_add_app(app);
+
+ /*
+ * Attach JUL application to a UST app object if one exists.
+ *
+ * FIXME: This implies that the UST app object exists and created before
+ * JUL registration. Must confirm or else JUL app will leak until socket is
+ * closed by the application.
+ */
+ jul_attach_app(app);
+
+ return new_sock->fd;
+
+error_socket:
+ new_sock->ops->close(new_sock);
+ lttcomm_destroy_sock(new_sock);
+error:
+ return ret;
+}
+
+/*
+ * This thread manage application notify communication.
+ */
+void *jul_thread_manage_registration(void *data)
+{
+ int i, ret, pollfd;
+ uint32_t revents, nb_fd;
+ struct lttng_poll_event events;
+ struct lttcomm_sock *reg_sock;
+
+ DBG("[jul-thread] Manage JUL application registration.");
+
+ rcu_register_thread();
+ rcu_thread_online();
+
+ /* JUL initialization call MUST be called before starting the thread. */
+ assert(jul_apps_ht_by_sock);
+
+ /* Create pollset with size 2, quit pipe and socket. */
+ ret = sessiond_set_thread_pollset(&events, 2);
+ if (ret < 0) {
+ goto error_poll_create;
+ }
+
+ reg_sock = init_tcp_socket();
+ if (!reg_sock) {
+ goto error_tcp_socket;
+ }
+
+ /* Add create valid TCP socket to poll set. */
+ ret = lttng_poll_add(&events, reg_sock->fd,
+ LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
+ if (ret < 0) {
+ goto error;
+ }
+
+ while (1) {
+ DBG3("[jul-thread] Manage JUL polling on %d fds",
+ LTTNG_POLL_GETNB(&events));
+
+ /* Inifinite blocking call, waiting for transmission */
+restart:
+ ret = lttng_poll_wait(&events, -1);
+ if (ret < 0) {
+ /*
+ * Restart interrupted system call.
+ */
+ if (errno == EINTR) {
+ goto restart;
+ }
+ goto error;
+ }
+ nb_fd = ret;
+ DBG3("[jul-thread] %d fd ready", nb_fd);
+
+ for (i = 0; i < nb_fd; i++) {
+ /* Fetch once the poll data */
+ revents = LTTNG_POLL_GETEV(&events, i);
+ pollfd = LTTNG_POLL_GETFD(&events, i);
+
+ /* Thread quit pipe has been closed. Killing thread. */
+ ret = sessiond_check_thread_quit_pipe(pollfd, revents);
+ if (ret) {
+ goto exit;
+ }
+
+ /*
+ * Check first if this is a POLLERR since POLLIN is also included
+ * in an error value thus checking first.
+ */
+ if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+ /* Removing from the poll set */
+ ret = lttng_poll_del(&events, pollfd);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /*
+ * FIXME: Should we try to invalidate the JUL socket in the
+ * associated ust app.
+ */
+ destroy_jul_app(pollfd);
+ } else if (revents & (LPOLLIN)) {
+ int new_fd;
+
+ /* Pollin event of JUL app socket should NEVER happen. */
+ assert(pollfd == reg_sock->fd);
+
+ new_fd = handle_registration(reg_sock);
+ if (new_fd < 0) {
+ WARN("[jul-thread] JUL registration failed. Ignoring.");
+ /* Somehow the communication failed. Just continue. */
+ continue;
+ }
+
+ /* Only add poll error event to only detect shutdown. */
+ ret = lttng_poll_add(&events, new_fd,
+ LPOLLERR | LPOLLHUP | LPOLLRDHUP);
+ if (ret < 0) {
+ destroy_jul_app(new_fd);
+ continue;
+ }
+
+ /* Update newly registered app. */
+ update_jul_app(new_fd);
+ } else {
+ ERR("Unknown poll events %u for sock %d", revents, pollfd);
+ continue;
+ }
+ }
+ }
+
+exit:
+ /* Whatever happens, try to delete it and exit. */
+ (void) lttng_poll_del(&events, reg_sock->fd);
+error:
+ destroy_tcp_socket(reg_sock);
+error_tcp_socket:
+ lttng_poll_clean(&events);
+error_poll_create:
+ DBG("[jul-thread] is cleaning up and stopping.");
+
+ if (jul_apps_ht_by_sock) {
+ clean_jul_apps_ht();
+ lttng_ht_destroy(jul_apps_ht_by_sock);
+ }
+
+ rcu_thread_offline();
+ rcu_unregister_thread();
+ return NULL;
+}
projects / lttng-tools.git / blobdiff