--- /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 <common/shm.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 "utils.h"
+#include "thread.h"
+
+struct thread_state {
+ struct lttng_pipe *quit_pipe;
+ struct ust_cmd_queue *ust_cmd_queue;
+ sem_t ready;
+ bool running;
+ int application_socket;
+};
+
+/*
+ * 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(
+ the_config.apps_unix_sock_path.value);
+ if (apps_sock < 0) {
+ ERR("Create unix sock failed: %s",
+ the_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(the_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",
+ the_config.apps_unix_sock_path.value);
+ goto error_close_socket;
+ }
+
+ DBG3("Session daemon application socket created (fd = %d) ", apps_sock);
+ ret = apps_sock;
+end:
+ umask(old_umask);
+ return ret;
+error_close_socket:
+ if (close(apps_sock)) {
+ PERROR("Failed to close application socket in error path");
+ }
+ apps_sock = -1;
+ ret = -1;
+ goto end;
+}
+
+/*
+ * 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(
+ the_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_state *thread_state = (struct thread_state *) data;
+
+ if (!data) {
+ return;
+ }
+
+ lttng_pipe_destroy(thread_state->quit_pipe);
+ free(thread_state);
+}
+
+static void set_thread_status(struct thread_state *thread_state, bool running)
+{
+ DBG("Marking application registration thread's state as %s", running ? "running" : "error");
+ thread_state->running = running;
+ sem_post(&thread_state->ready);
+}
+
+static bool wait_thread_status(struct thread_state *thread_state)
+{
+ DBG("Waiting for application registration thread to be ready");
+ sem_wait(&thread_state->ready);
+ if (thread_state->running) {
+ DBG("Application registration thread is ready");
+ } else {
+ ERR("Initialization of application registration thread failed");
+ }
+
+ return thread_state->running;
+}
+
+static void thread_init_cleanup(void *data)
+{
+ struct thread_state *thread_state = (struct thread_state *) data;
+
+ set_thread_status(thread_state, false);
+}
+
+/*
+ * This thread manage application registration.
+ */
+static void *thread_application_registration(void *data)
+{
+ int sock = -1, i, ret, pollfd, err = -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_state *thread_state = (struct thread_state *) data;
+ const int application_socket = thread_state->application_socket;
+ const int quit_pipe_read_fd = lttng_pipe_get_readfd(
+ thread_state->quit_pipe);
+
+ DBG("[thread] Manage application registration started");
+
+ pthread_cleanup_push(thread_init_cleanup, thread_state);
+ health_register(the_health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG);
+
+ ret = lttcomm_listen_unix_sock(application_socket);
+ 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, application_socket, 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;
+ }
+
+ set_thread_status(thread_state, true);
+ pthread_cleanup_pop(0);
+
+ if (testpoint(sessiond_thread_registration_apps)) {
+ goto error_poll_add;
+ }
+
+ 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);
+
+ /* 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(application_socket);
+ 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 (the_config.app_socket_timeout >= 0) {
+ (void) lttcomm_setsockopt_rcv_timeout(sock,
+ the_config.app_socket_timeout * 1000);
+ (void) lttcomm_setsockopt_snd_timeout(sock,
+ the_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 = (ust_command *) zmalloc(sizeof(struct ust_command));
+ if (ust_cmd == NULL) {
+ PERROR("ust command zmalloc");
+ ret = close(sock);
+ if (ret) {
+ PERROR("close");
+ }
+ sock = -1;
+ 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_head_ptr_t head;
+ head.h = &thread_state->ust_cmd_queue->head;
+ cds_wfcq_enqueue(head,
+ &thread_state->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(&thread_state->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);
+
+ ret = close(application_socket);
+ if (ret) {
+ PERROR("Failed to close application registration socket");
+ }
+ if (sock >= 0) {
+ ret = close(sock);
+ if (ret) {
+ PERROR("Failed to close application socket");
+ }
+ lttng_fd_put(LTTNG_FD_APPS, 1);
+ }
+ unlink(the_config.apps_unix_sock_path.value);
+
+error_poll_add:
+ lttng_poll_clean(&events);
+error_listen:
+error_create_poll:
+ DBG("UST Registration thread cleanup complete");
+ if (err) {
+ health_error();
+ ERR("Health error occurred in %s", __func__);
+ }
+ health_unregister(the_health_sessiond);
+ return NULL;
+}
+
+static bool shutdown_application_registration_thread(void *data)
+{
+ struct thread_state *thread_state = (struct thread_state *) data;
+ const int write_fd = lttng_pipe_get_writefd(thread_state->quit_pipe);
+
+ return notify_thread_pipe(write_fd) == 1;
+}
+
+struct lttng_thread *launch_application_registration_thread(
+ struct ust_cmd_queue *cmd_queue)
+{
+ int ret;
+ struct lttng_pipe *quit_pipe;
+ struct thread_state *thread_state = NULL;
+ struct lttng_thread *thread = NULL;
+ const bool is_root = (getuid() == 0);
+ int application_socket = -1;
+
+ thread_state = (struct thread_state *) zmalloc(sizeof(*thread_state));
+ if (!thread_state) {
+ goto error_alloc;
+ }
+ quit_pipe = lttng_pipe_open(FD_CLOEXEC);
+ if (!quit_pipe) {
+ goto error;
+ }
+ thread_state->quit_pipe = quit_pipe;
+ thread_state->ust_cmd_queue = cmd_queue;
+ application_socket = create_application_socket();
+ if (application_socket < 0) {
+ goto error;
+ }
+ thread_state->application_socket = application_socket;
+ sem_init(&thread_state->ready, 0, 0);
+
+ thread = lttng_thread_create("UST application registration",
+ thread_application_registration,
+ shutdown_application_registration_thread,
+ cleanup_application_registration_thread,
+ thread_state);
+ if (!thread) {
+ goto error;
+ }
+ /*
+ * The application registration thread now owns the application socket
+ * and the global thread state. The thread state is used to wait for
+ * the thread's status, but its ownership now belongs to the thread.
+ */
+ application_socket = -1;
+ if (!wait_thread_status(thread_state)) {
+ thread_state = NULL;
+ goto error;
+ }
+
+ /* 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 problems for already\n"
+ "running applications that wishes to register.");
+ }
+
+ return thread;
+error:
+ lttng_thread_put(thread);
+ cleanup_application_registration_thread(thread_state);
+ if (application_socket >= 0) {
+ if (close(application_socket)) {
+ PERROR("Failed to close application registration socket");
+ }
+ }
+error_alloc:
+ return NULL;
+}
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