--- /dev/null
+/*
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+
+#include <common/common.h>
+#include <common/sessiond-comm/sessiond-comm.h>
+#include <common/uri.h>
+#include <common/utils.h>
+
+#include <common/compat/endian.h>
+
+#include "fd-limit.h"
+#include "agent-thread.h"
+#include "agent.h"
+#include "lttng-sessiond.h"
+#include "session.h"
+#include "utils.h"
+#include "thread.h"
+
+struct thread_notifiers {
+ struct lttng_pipe *quit_pipe;
+ sem_t ready;
+};
+
+struct agent_app_id {
+ pid_t pid;
+ enum lttng_domain_type domain;
+};
+
+struct agent_protocol_version {
+ unsigned int major, minor;
+};
+
+static int agent_tracing_enabled = -1;
+
+/*
+ * 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://" DEFAULT_NETWORK_VIEWER_BIND_ADDRESS;
+
+/*
+ * Update agent application using the given socket. This is done just after
+ * registration was successful.
+ *
+ * This will acquire the various sessions' lock; none must be held by the
+ * caller.
+ * The caller must hold the session list lock.
+ */
+static void update_agent_app(const struct agent_app *app)
+{
+ struct ltt_session *session, *stmp;
+ struct ltt_session_list *list;
+ struct agent *trigger_agent;
+ struct lttng_ht_iter iter;
+
+ list = session_get_list();
+ LTTNG_ASSERT(list);
+
+ cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
+ if (!session_get(session)) {
+ continue;
+ }
+
+ session_lock(session);
+ if (session->ust_session) {
+ const struct agent *agt;
+
+ rcu_read_lock();
+ agt = trace_ust_find_agent(session->ust_session, app->domain);
+ if (agt) {
+ agent_update(agt, app);
+ }
+ rcu_read_unlock();
+ }
+ session_unlock(session);
+ session_put(session);
+ }
+
+ rcu_read_lock();
+ /*
+ * We are protected against the addition of new events by the session
+ * list lock being held.
+ */
+ cds_lfht_for_each_entry(the_trigger_agents_ht_by_domain->ht,
+ &iter.iter, trigger_agent, node.node) {
+ agent_update(trigger_agent, app);
+ }
+ 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;
+ unsigned int port;
+ bool bind_succeeded = false;
+
+ /*
+ * 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);
+ LTTNG_ASSERT(ret);
+ LTTNG_ASSERT(the_config.agent_tcp_port.begin > 0);
+ uri->port = the_config.agent_tcp_port.begin;
+
+ sock = lttcomm_alloc_sock_from_uri(uri);
+ uri_free(uri);
+ if (sock == NULL) {
+ ERR("agent allocating TCP socket");
+ goto error;
+ }
+
+ ret = lttcomm_create_sock(sock);
+ if (ret < 0) {
+ goto error;
+ }
+
+ for (port = the_config.agent_tcp_port.begin;
+ port <= the_config.agent_tcp_port.end; port++) {
+ ret = lttcomm_sock_set_port(sock, (uint16_t) port);
+ if (ret) {
+ ERR("Failed to set port %u on socket",
+ port);
+ goto error;
+ }
+ DBG3("Trying to bind on port %u", port);
+ ret = sock->ops->bind(sock);
+ if (!ret) {
+ bind_succeeded = true;
+ break;
+ }
+
+ if (errno == EADDRINUSE) {
+ DBG("Failed to bind to port %u since it is already in use",
+ port);
+ } else {
+ PERROR("Failed to bind to port %u", port);
+ goto error;
+ }
+ }
+
+ if (!bind_succeeded) {
+ if (the_config.agent_tcp_port.begin ==
+ the_config.agent_tcp_port.end) {
+ WARN("Another process is already using the agent port %i. "
+ "Agent support will be deactivated.",
+ the_config.agent_tcp_port.begin);
+ goto error;
+ } else {
+ WARN("All ports in the range [%i, %i] are already in use. "
+ "Agent support will be deactivated.",
+ the_config.agent_tcp_port.begin,
+ the_config.agent_tcp_port.end);
+ goto error;
+ }
+ }
+
+ ret = sock->ops->listen(sock, -1);
+ if (ret < 0) {
+ goto error;
+ }
+
+ DBG("Listening on TCP port %u and socket %d",
+ 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)
+{
+ int ret;
+ uint16_t port;
+
+ LTTNG_ASSERT(sock);
+
+ ret = lttcomm_sock_get_port(sock, &port);
+ if (ret) {
+ ERR("Failed to get port of agent TCP socket");
+ port = 0;
+ }
+
+ DBG3("Destroy TCP socket on port %" PRIu16,
+ port);
+
+ /* This will return gracefully if fd is invalid. */
+ sock->ops->close(sock);
+ lttcomm_destroy_sock(sock);
+}
+
+static const char *domain_type_str(enum lttng_domain_type domain_type)
+{
+ switch (domain_type) {
+ case LTTNG_DOMAIN_NONE:
+ return "none";
+ case LTTNG_DOMAIN_KERNEL:
+ return "kernel";
+ case LTTNG_DOMAIN_UST:
+ return "ust";
+ case LTTNG_DOMAIN_JUL:
+ return "jul";
+ case LTTNG_DOMAIN_LOG4J:
+ return "log4j";
+ case LTTNG_DOMAIN_PYTHON:
+ return "python";
+ default:
+ return "unknown";
+ }
+}
+
+static bool is_agent_protocol_version_supported(
+ const struct agent_protocol_version *version)
+{
+ const bool is_supported = version->major == AGENT_MAJOR_VERSION &&
+ version->minor == AGENT_MINOR_VERSION;
+
+ if (!is_supported) {
+ WARN("Refusing agent connection: unsupported protocol version %ui.%ui, expected %i.%i",
+ version->major, version->minor,
+ AGENT_MAJOR_VERSION, AGENT_MINOR_VERSION);
+ }
+
+ return is_supported;
+}
+
+/*
+ * Handle a new agent connection on the registration socket.
+ *
+ * Returns 0 on success, or else a negative errno value.
+ * On success, the resulting socket is returned through `agent_app_socket`
+ * and the application's reported id is updated through `agent_app_id`.
+ */
+static int accept_agent_connection(
+ struct lttcomm_sock *reg_sock,
+ struct agent_app_id *agent_app_id,
+ struct lttcomm_sock **agent_app_socket)
+{
+ int ret;
+ struct agent_protocol_version agent_version;
+ ssize_t size;
+ struct agent_register_msg msg;
+ struct lttcomm_sock *new_sock;
+
+ LTTNG_ASSERT(reg_sock);
+
+ new_sock = reg_sock->ops->accept(reg_sock);
+ if (!new_sock) {
+ ret = -ENOTCONN;
+ goto end;
+ }
+
+ size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
+ if (size < sizeof(msg)) {
+ if (size < 0) {
+ PERROR("Failed to register new agent application");
+ } else if (size != 0) {
+ ERR("Failed to register new agent application: invalid registration message length: expected length = %zu, message length = %zd",
+ sizeof(msg), size);
+ } else {
+ DBG("Failed to register new agent application: connection closed");
+ }
+ ret = -EINVAL;
+ goto error_close_socket;
+ }
+
+ agent_version = (struct agent_protocol_version) {
+ be32toh(msg.major_version),
+ be32toh(msg.minor_version),
+ };
+
+ /* Test communication protocol version of the registering agent. */
+ if (!is_agent_protocol_version_supported(&agent_version)) {
+ ret = -EINVAL;
+ goto error_close_socket;
+ }
+
+ *agent_app_id = (struct agent_app_id) {
+ .pid = (pid_t) be32toh(msg.pid),
+ .domain = (lttng_domain_type) be32toh(msg.domain),
+ };
+
+ DBG2("New registration for agent application: pid = %ld, domain = %s, socket fd = %d",
+ (long) agent_app_id->pid,
+ domain_type_str(agent_app_id->domain), new_sock->fd);
+
+ *agent_app_socket = new_sock;
+ new_sock = NULL;
+ ret = 0;
+ goto end;
+
+error_close_socket:
+ new_sock->ops->close(new_sock);
+ lttcomm_destroy_sock(new_sock);
+end:
+ return ret;
+}
+
+bool agent_tracing_is_enabled(void)
+{
+ int enabled;
+
+ enabled = uatomic_read(&agent_tracing_enabled);
+ LTTNG_ASSERT(enabled != -1);
+ return enabled == 1;
+}
+
+/*
+ * Write agent TCP port using the rundir.
+ */
+static int write_agent_port(uint16_t port)
+{
+ return utils_create_pid_file(
+ (pid_t) port, the_config.agent_port_file_path.value);
+}
+
+static
+void mark_thread_as_ready(struct thread_notifiers *notifiers)
+{
+ DBG("Marking agent management thread as ready");
+ sem_post(¬ifiers->ready);
+}
+
+static
+void wait_until_thread_is_ready(struct thread_notifiers *notifiers)
+{
+ DBG("Waiting for agent management thread to be ready");
+ sem_wait(¬ifiers->ready);
+ DBG("Agent management thread is ready");
+}
+
+/*
+ * This thread manage application notify communication.
+ */
+static void *thread_agent_management(void *data)
+{
+ int i, ret, pollfd;
+ uint32_t revents, nb_fd;
+ struct lttng_poll_event events;
+ struct lttcomm_sock *reg_sock;
+ struct thread_notifiers *notifiers = (thread_notifiers *) data;
+ const int quit_pipe_read_fd = lttng_pipe_get_readfd(
+ notifiers->quit_pipe);
+
+ DBG("Manage agent application registration.");
+
+ rcu_register_thread();
+ rcu_thread_online();
+
+ /* Agent initialization call MUST be called before starting the thread. */
+ LTTNG_ASSERT(the_agent_apps_ht_by_sock);
+
+ /* Create pollset with size 2, quit pipe and registration socket. */
+ ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
+ if (ret < 0) {
+ goto error_poll_create;
+ }
+
+ ret = lttng_poll_add(&events, quit_pipe_read_fd,
+ LPOLLIN | LPOLLERR);
+ if (ret < 0) {
+ goto error_tcp_socket;
+ }
+
+ reg_sock = init_tcp_socket();
+ if (reg_sock) {
+ uint16_t port;
+
+ ret = lttcomm_sock_get_port(reg_sock, &port);
+ LTTNG_ASSERT(ret == 0);
+
+ ret = write_agent_port(port);
+ if (ret) {
+ ERR("Failed to create agent port file: agent tracing will be unavailable");
+ /* Don't prevent the launch of the sessiond on error. */
+ mark_thread_as_ready(notifiers);
+ goto error;
+ }
+ } else {
+ /* Don't prevent the launch of the sessiond on error. */
+ mark_thread_as_ready(notifiers);
+ goto error_tcp_socket;
+ }
+
+ /*
+ * Signal that the agent thread is ready. The command thread
+ * may start to query whether or not agent tracing is enabled.
+ */
+ uatomic_set(&agent_tracing_enabled, 1);
+ mark_thread_as_ready(notifiers);
+
+ /* Add TCP socket to the poll set. */
+ ret = lttng_poll_add(&events, reg_sock->fd,
+ LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
+ if (ret < 0) {
+ goto error;
+ }
+
+ while (1) {
+ DBG3("Manage agent polling");
+
+ /* Inifinite blocking call, waiting for transmission */
+restart:
+ ret = lttng_poll_wait(&events, -1);
+ DBG3("Manage agent return from poll on %d fds",
+ LTTNG_POLL_GETNB(&events));
+ if (ret < 0) {
+ /*
+ * Restart interrupted system call.
+ */
+ if (errno == EINTR) {
+ goto restart;
+ }
+ goto error;
+ }
+ nb_fd = ret;
+ DBG3("%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. */
+ if (pollfd == quit_pipe_read_fd) {
+ goto exit;
+ }
+
+ /* Activity on the registration socket. */
+ if (revents & LPOLLIN) {
+ struct agent_app_id new_app_id;
+ struct agent_app *new_app = NULL;
+ struct lttcomm_sock *new_app_socket;
+ int new_app_socket_fd;
+
+ LTTNG_ASSERT(pollfd == reg_sock->fd);
+
+ ret = accept_agent_connection(
+ reg_sock, &new_app_id, &new_app_socket);
+ if (ret < 0) {
+ /* Errors are already logged. */
+ continue;
+ }
+
+ /*
+ * new_app_socket's ownership has been
+ * transferred to the new agent app.
+ */
+ new_app = agent_create_app(new_app_id.pid,
+ new_app_id.domain,
+ new_app_socket);
+ if (!new_app) {
+ new_app_socket->ops->close(
+ new_app_socket);
+ continue;
+ }
+ new_app_socket_fd = new_app_socket->fd;
+ new_app_socket = NULL;
+
+ /*
+ * Since this is a command socket (write then
+ * read), only add poll error event to only
+ * detect shutdown.
+ */
+ ret = lttng_poll_add(&events, new_app_socket_fd,
+ LPOLLERR | LPOLLHUP | LPOLLRDHUP);
+ if (ret < 0) {
+ agent_destroy_app(new_app);
+ continue;
+ }
+
+ /*
+ * Prevent sessions from being modified while
+ * the agent application's configuration is
+ * updated.
+ */
+ session_lock_list();
+
+ /*
+ * Update the newly registered applications's
+ * configuration.
+ */
+ update_agent_app(new_app);
+
+ ret = agent_send_registration_done(new_app);
+ if (ret < 0) {
+ agent_destroy_app(new_app);
+ /* Removing from the poll set. */
+ ret = lttng_poll_del(&events,
+ new_app_socket_fd);
+ if (ret < 0) {
+ session_unlock_list();
+ goto error;
+ }
+ continue;
+ }
+
+ /* Publish the new agent app. */
+ agent_add_app(new_app);
+
+ session_unlock_list();
+ } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+ /* Removing from the poll set */
+ ret = lttng_poll_del(&events, pollfd);
+ if (ret < 0) {
+ goto error;
+ }
+ agent_destroy_app_by_sock(pollfd);
+ } else {
+ ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+ goto error;
+ }
+ }
+ }
+
+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:
+ uatomic_set(&agent_tracing_enabled, 0);
+ DBG("Cleaning up and stopping.");
+ rcu_thread_offline();
+ rcu_unregister_thread();
+ return NULL;
+}
+
+static bool shutdown_agent_management_thread(void *data)
+{
+ struct thread_notifiers *notifiers = (thread_notifiers *) data;
+ const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe);
+
+ return notify_thread_pipe(write_fd) == 1;
+}
+
+static void cleanup_agent_management_thread(void *data)
+{
+ struct thread_notifiers *notifiers = (thread_notifiers *) data;
+
+ lttng_pipe_destroy(notifiers->quit_pipe);
+ sem_destroy(¬ifiers->ready);
+ free(notifiers);
+}
+
+bool launch_agent_management_thread(void)
+{
+ struct thread_notifiers *notifiers;
+ struct lttng_thread *thread;
+
+ notifiers = (thread_notifiers *) zmalloc(sizeof(*notifiers));
+ if (!notifiers) {
+ goto error_alloc;
+ }
+
+ sem_init(¬ifiers->ready, 0, 0);
+ notifiers->quit_pipe = lttng_pipe_open(FD_CLOEXEC);
+ if (!notifiers->quit_pipe) {
+ goto error;
+ }
+ thread = lttng_thread_create("Agent management",
+ thread_agent_management,
+ shutdown_agent_management_thread,
+ cleanup_agent_management_thread,
+ notifiers);
+ if (!thread) {
+ goto error;
+ }
+ wait_until_thread_is_ready(notifiers);
+ lttng_thread_put(thread);
+ return true;
+error:
+ cleanup_agent_management_thread(notifiers);
+error_alloc:
+ return false;
+}
projects / lttng-tools.git / blobdiff