+/*
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * 2013 - Jérémie Galarneau <jeremie.galarneau@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.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <urcu.h>
+#include <common/futex.h>
+#include <common/macros.h>
+#include <common/utils.h>
+#include <sys/stat.h>
+
+#include "register.h"
+#include "lttng-sessiond.h"
+#include "testpoint.h"
+#include "health-sessiond.h"
+#include "fd-limit.h"
+#include "shm.h"
+#include "utils.h"
+#include "thread.h"
+
+struct thread_notifiers {
+ struct lttng_pipe *quit_pipe;
+ struct ust_cmd_queue *ust_cmd_queue;
+};
+
+/*
+ * Creates the application socket.
+ */
+static int create_application_socket(void)
+{
+ int ret = 0;
+ int apps_sock;
+ const mode_t old_umask = umask(0);
+
+ /* Create the application unix socket */
+ apps_sock = lttcomm_create_unix_sock(config.apps_unix_sock_path.value);
+ if (apps_sock < 0) {
+ ERR("Create unix sock failed: %s", config.apps_unix_sock_path.value);
+ ret = -1;
+ goto end;
+ }
+
+ /* Set the cloexec flag */
+ ret = utils_set_fd_cloexec(apps_sock);
+ if (ret < 0) {
+ ERR("Unable to set CLOEXEC flag to the app Unix socket (fd: %d). "
+ "Continuing but note that the consumer daemon will have a "
+ "reference to this socket on exec()", apps_sock);
+ }
+
+ /* File permission MUST be 666 */
+ ret = chmod(config.apps_unix_sock_path.value,
+ S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
+ if (ret < 0) {
+ PERROR("Set file permissions failed on %s",
+ config.apps_unix_sock_path.value);
+ goto end;
+ }
+
+ DBG3("Session daemon application socket created (fd = %d) ", apps_sock);
+ ret = apps_sock;
+end:
+ umask(old_umask);
+ return ret;
+}
+
+/*
+ * Notify UST applications using the shm mmap futex.
+ */
+static int notify_ust_apps(int active, bool is_root)
+{
+ char *wait_shm_mmap;
+
+ DBG("Notifying applications of session daemon state: %d", active);
+
+ /* See shm.c for this call implying mmap, shm and futex calls */
+ wait_shm_mmap = shm_ust_get_mmap(config.wait_shm_path.value, is_root);
+ if (wait_shm_mmap == NULL) {
+ goto error;
+ }
+
+ /* Wake waiting process */
+ futex_wait_update((int32_t *) wait_shm_mmap, active);
+
+ /* Apps notified successfully */
+ return 0;
+
+error:
+ return -1;
+}
+
+static void cleanup_application_registration_thread(void *data)
+{
+ struct thread_notifiers *notifiers = data;
+
+ lttng_pipe_destroy(notifiers->quit_pipe);
+ free(notifiers);
+}
+
+/*
+ * This thread manage application registration.
+ */
+static void *thread_application_registration(void *data)
+{
+ int sock = -1, i, ret, pollfd, err = -1;
+ int apps_sock = -1;
+ uint32_t revents, nb_fd;
+ struct lttng_poll_event events;
+ /*
+ * Gets allocated in this thread, enqueued to a global queue, dequeued
+ * and freed in the manage apps thread.
+ */
+ struct ust_command *ust_cmd = NULL;
+ const bool is_root = (getuid() == 0);
+ struct thread_notifiers *notifiers = data;
+ const int quit_pipe_read_fd = lttng_pipe_get_readfd(
+ notifiers->quit_pipe);
+
+ DBG("[thread] Manage application registration started");
+
+ health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG);
+
+ if (testpoint(sessiond_thread_registration_apps)) {
+ goto error_testpoint;
+ }
+
+ apps_sock = create_application_socket();
+ if (apps_sock < 0) {
+ goto error_listen;
+ }
+
+ ret = lttcomm_listen_unix_sock(apps_sock);
+ if (ret < 0) {
+ goto error_listen;
+ }
+
+ /*
+ * Pass 2 as size here for the thread quit pipe and apps_sock. Nothing
+ * more will be added to this poll set.
+ */
+ ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
+ if (ret < 0) {
+ goto error_create_poll;
+ }
+
+ /* Add the application registration socket */
+ ret = lttng_poll_add(&events, apps_sock, LPOLLIN | LPOLLRDHUP);
+ if (ret < 0) {
+ goto error_poll_add;
+ }
+
+ /* Add the application registration socket */
+ ret = lttng_poll_add(&events, quit_pipe_read_fd, LPOLLIN | LPOLLRDHUP);
+ if (ret < 0) {
+ goto error_poll_add;
+ }
+
+ /* Notify all applications to register */
+ ret = notify_ust_apps(1, is_root);
+ if (ret < 0) {
+ ERR("Failed to notify applications or create the wait shared memory.\n"
+ "Execution continues but there might be problem for already\n"
+ "running applications that wishes to register.");
+ }
+
+ while (1) {
+ DBG("Accepting application registration");
+
+ /* Inifinite blocking call, waiting for transmission */
+ restart:
+ health_poll_entry();
+ ret = lttng_poll_wait(&events, -1);
+ health_poll_exit();
+ if (ret < 0) {
+ /*
+ * Restart interrupted system call.
+ */
+ if (errno == EINTR) {
+ goto restart;
+ }
+ goto error;
+ }
+
+ nb_fd = ret;
+
+ for (i = 0; i < nb_fd; i++) {
+ health_code_update();
+
+ /* Fetch once the poll data */
+ revents = LTTNG_POLL_GETEV(&events, i);
+ pollfd = LTTNG_POLL_GETFD(&events, i);
+
+ if (!revents) {
+ /* No activity for this FD (poll implementation). */
+ continue;
+ }
+
+ /* Thread quit pipe has been closed. Killing thread. */
+ if (pollfd == quit_pipe_read_fd) {
+ err = 0;
+ goto exit;
+ } else {
+ /* Event on the registration socket */
+ if (revents & LPOLLIN) {
+ sock = lttcomm_accept_unix_sock(apps_sock);
+ if (sock < 0) {
+ goto error;
+ }
+
+ /*
+ * Set socket timeout for both receiving and ending.
+ * app_socket_timeout is in seconds, whereas
+ * lttcomm_setsockopt_rcv_timeout and
+ * lttcomm_setsockopt_snd_timeout expect msec as
+ * parameter.
+ */
+ if (config.app_socket_timeout >= 0) {
+ (void) lttcomm_setsockopt_rcv_timeout(sock,
+ config.app_socket_timeout * 1000);
+ (void) lttcomm_setsockopt_snd_timeout(sock,
+ config.app_socket_timeout * 1000);
+ }
+
+ /*
+ * Set the CLOEXEC flag. Return code is useless because
+ * either way, the show must go on.
+ */
+ (void) utils_set_fd_cloexec(sock);
+
+ /* Create UST registration command for enqueuing */
+ ust_cmd = zmalloc(sizeof(struct ust_command));
+ if (ust_cmd == NULL) {
+ PERROR("ust command zmalloc");
+ ret = close(sock);
+ if (ret) {
+ PERROR("close");
+ }
+ goto error;
+ }
+
+ /*
+ * Using message-based transmissions to ensure we don't
+ * have to deal with partially received messages.
+ */
+ ret = lttng_fd_get(LTTNG_FD_APPS, 1);
+ if (ret < 0) {
+ ERR("Exhausted file descriptors allowed for applications.");
+ free(ust_cmd);
+ ret = close(sock);
+ if (ret) {
+ PERROR("close");
+ }
+ sock = -1;
+ continue;
+ }
+
+ health_code_update();
+ ret = ust_app_recv_registration(sock, &ust_cmd->reg_msg);
+ if (ret < 0) {
+ free(ust_cmd);
+ /* Close socket of the application. */
+ ret = close(sock);
+ if (ret) {
+ PERROR("close");
+ }
+ lttng_fd_put(LTTNG_FD_APPS, 1);
+ sock = -1;
+ continue;
+ }
+ health_code_update();
+
+ ust_cmd->sock = sock;
+ sock = -1;
+
+ DBG("UST registration received with 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);
+
+ /*
+ * Lock free enqueue the registration request. The red pill
+ * has been taken! This apps will be part of the *system*.
+ */
+ cds_wfcq_enqueue(¬ifiers->ust_cmd_queue->head,
+ ¬ifiers->ust_cmd_queue->tail,
+ &ust_cmd->node);
+
+ /*
+ * Wake the registration queue futex. Implicit memory
+ * barrier with the exchange in cds_wfcq_enqueue.
+ */
+ futex_nto1_wake(¬ifiers->ust_cmd_queue->futex);
+ } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+ ERR("Register apps socket poll error");
+ goto error;
+ } else {
+ ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+ goto error;
+ }
+ }
+ }
+ }
+
+exit:
+error:
+ /* Notify that the registration thread is gone */
+ notify_ust_apps(0, is_root);
+
+ if (apps_sock >= 0) {
+ ret = close(apps_sock);
+ if (ret) {
+ PERROR("close");
+ }
+ }
+ if (sock >= 0) {
+ ret = close(sock);
+ if (ret) {
+ PERROR("close");
+ }
+ lttng_fd_put(LTTNG_FD_APPS, 1);
+ }
+ unlink(config.apps_unix_sock_path.value);
+
+error_poll_add:
+ lttng_poll_clean(&events);
+error_listen:
+error_create_poll:
+error_testpoint:
+ DBG("UST Registration thread cleanup complete");
+ if (err) {
+ health_error();
+ ERR("Health error occurred in %s", __func__);
+ }
+ health_unregister(health_sessiond);
+ return NULL;
+}
+
+static bool shutdown_application_registration_thread(void *data)
+{
+ struct thread_notifiers *notifiers = data;
+ const int write_fd = lttng_pipe_get_writefd(notifiers->quit_pipe);
+
+ return notify_thread_pipe(write_fd) == 1;
+}
+
+bool launch_application_registration_thread(
+ struct ust_cmd_queue *cmd_queue)
+{
+ struct lttng_pipe *quit_pipe;
+ struct thread_notifiers *notifiers = NULL;
+ struct lttng_thread *thread;
+
+ quit_pipe = lttng_pipe_open(FD_CLOEXEC);
+ if (!quit_pipe) {
+ goto error;
+ }
+
+ notifiers = zmalloc(sizeof(*notifiers));
+ if (!notifiers) {
+ goto error;
+ }
+ notifiers->quit_pipe = quit_pipe;
+ notifiers->ust_cmd_queue = cmd_queue;
+
+ thread = lttng_thread_create("UST application registration",
+ thread_application_registration,
+ shutdown_application_registration_thread,
+ cleanup_application_registration_thread,
+ notifiers);
+ if (!thread) {
+ goto error;
+ }
+ lttng_thread_put(thread);
+ return true;
+error:
+ cleanup_application_registration_thread(notifiers);
+ return false;
+}
projects / lttng-tools.git / commitdiff
