+/*
+ * Copyright (C) 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+#include <fcntl.h>
+#include <getopt.h>
+#include <grp.h>
+#include <limits.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ipc.h>
+#include <sys/resource.h>
+#include <sys/shm.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <urcu/list.h>
+#include <poll.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <urcu/compiler.h>
+#include <ulimit.h>
+#include <inttypes.h>
+
+#include <common/defaults.h>
+#include <common/common.h>
+#include <common/consumer/consumer.h>
+#include <common/consumer/consumer-timer.h>
+#include <common/compat/poll.h>
+#include <common/sessiond-comm/sessiond-comm.h>
+#include <common/utils.h>
+
+#include "lttng-consumerd.h"
+#include "health-consumerd.h"
+
+/* Global health check unix path */
+static char health_unix_sock_path[PATH_MAX];
+
+int health_quit_pipe[2];
+
+/*
+ * Check if the thread quit pipe was triggered.
+ *
+ * Return 1 if it was triggered else 0;
+ */
+static
+int check_health_quit_pipe(int fd, uint32_t events)
+{
+ if (fd == health_quit_pipe[0] && (events & LPOLLIN)) {
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Send data on a unix socket using the liblttsessiondcomm API.
+ *
+ * Return lttcomm error code.
+ */
+static int send_unix_sock(int sock, void *buf, size_t len)
+{
+ /* Check valid length */
+ if (len == 0) {
+ return -1;
+ }
+
+ return lttcomm_send_unix_sock(sock, buf, len);
+}
+
+static
+int setup_health_path(void)
+{
+ int is_root, ret = 0;
+ enum lttng_consumer_type type;
+ const char *home_path;
+
+ type = lttng_consumer_get_type();
+ is_root = !getuid();
+
+ if (is_root) {
+ if (strlen(health_unix_sock_path) != 0) {
+ goto end;
+ }
+ switch (type) {
+ case LTTNG_CONSUMER_KERNEL:
+ snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+ DEFAULT_GLOBAL_KCONSUMER_HEALTH_UNIX_SOCK);
+ break;
+ case LTTNG_CONSUMER64_UST:
+ snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+ DEFAULT_GLOBAL_USTCONSUMER64_HEALTH_UNIX_SOCK);
+ break;
+ case LTTNG_CONSUMER32_UST:
+ snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+ DEFAULT_GLOBAL_USTCONSUMER32_HEALTH_UNIX_SOCK);
+ break;
+ default:
+ ret = -EINVAL;
+ goto end;
+ }
+ } else {
+ home_path = utils_get_home_dir();
+ if (home_path == NULL) {
+ /* TODO: Add --socket PATH option */
+ ERR("Can't get HOME directory for sockets creation.");
+ ret = -EPERM;
+ goto end;
+ }
+
+ /* Set health check Unix path */
+ if (strlen(health_unix_sock_path) != 0) {
+ goto end;
+ }
+ switch (type) {
+ case LTTNG_CONSUMER_KERNEL:
+ snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+ DEFAULT_HOME_KCONSUMER_HEALTH_UNIX_SOCK, home_path);
+ break;
+ case LTTNG_CONSUMER64_UST:
+ snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+ DEFAULT_HOME_USTCONSUMER64_HEALTH_UNIX_SOCK, home_path);
+ break;
+ case LTTNG_CONSUMER32_UST:
+ snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
+ DEFAULT_HOME_USTCONSUMER32_HEALTH_UNIX_SOCK, home_path);
+ break;
+ default:
+ ret = -EINVAL;
+ goto end;
+ }
+ }
+end:
+ return ret;
+}
+
+/*
+ * Thread managing health check socket.
+ */
+void *thread_manage_health(void *data)
+{
+ int sock = -1, new_sock = -1, ret, i, pollfd, err = -1;
+ uint32_t revents, nb_fd;
+ struct lttng_poll_event events;
+ struct health_comm_msg msg;
+ struct health_comm_reply reply;
+ int is_root;
+
+ DBG("[thread] Manage health check started");
+
+ setup_health_path();
+
+ rcu_register_thread();
+
+ /* We might hit an error path before this is created. */
+ lttng_poll_init(&events);
+
+ /* Create unix socket */
+ sock = lttcomm_create_unix_sock(health_unix_sock_path);
+ if (sock < 0) {
+ ERR("Unable to create health check Unix socket");
+ err = -1;
+ goto error;
+ }
+
+ is_root = !getuid();
+ if (is_root) {
+ /* lttng health client socket path permissions */
+ gid_t gid;
+
+ ret = utils_get_group_id(tracing_group_name, true, &gid);
+ if (ret) {
+ /* Default to root group. */
+ gid = 0;
+ }
+
+ ret = chown(health_unix_sock_path, 0, gid);
+ if (ret < 0) {
+ ERR("Unable to set group on %s", health_unix_sock_path);
+ PERROR("chown");
+ err = -1;
+ goto error;
+ }
+
+ ret = chmod(health_unix_sock_path,
+ S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+ if (ret < 0) {
+ ERR("Unable to set permissions on %s", health_unix_sock_path);
+ PERROR("chmod");
+ err = -1;
+ goto error;
+ }
+ }
+
+ /*
+ * Set the CLOEXEC flag. Return code is useless because either way, the
+ * show must go on.
+ */
+ (void) utils_set_fd_cloexec(sock);
+
+ ret = lttcomm_listen_unix_sock(sock);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /* Size is set to 1 for the consumer_channel pipe */
+ ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC);
+ if (ret < 0) {
+ ERR("Poll set creation failed");
+ goto error;
+ }
+
+ ret = lttng_poll_add(&events, health_quit_pipe[0], LPOLLIN);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /* Add the application registration socket */
+ ret = lttng_poll_add(&events, sock, LPOLLIN | LPOLLPRI);
+ if (ret < 0) {
+ goto error;
+ }
+
+ /* Perform prior memory accesses before decrementing ready */
+ cmm_smp_mb__before_uatomic_dec();
+ uatomic_dec(<tng_consumer_ready);
+
+ while (1) {
+ DBG("Health check ready");
+
+ /* 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;
+
+ 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 = check_health_quit_pipe(pollfd, revents);
+ if (ret) {
+ err = 0;
+ goto exit;
+ }
+
+ /* Event on the registration socket */
+ if (pollfd == sock) {
+ if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)
+ && !(revents & LPOLLIN)) {
+ ERR("Health socket poll error");
+ goto error;
+ }
+ }
+ }
+
+ new_sock = lttcomm_accept_unix_sock(sock);
+ if (new_sock < 0) {
+ goto error;
+ }
+
+ /*
+ * Set the CLOEXEC flag. Return code is useless because either way, the
+ * show must go on.
+ */
+ (void) utils_set_fd_cloexec(new_sock);
+
+ DBG("Receiving data from client for health...");
+ ret = lttcomm_recv_unix_sock(new_sock, (void *)&msg, sizeof(msg));
+ if (ret <= 0) {
+ DBG("Nothing recv() from client... continuing");
+ ret = close(new_sock);
+ if (ret) {
+ PERROR("close");
+ }
+ new_sock = -1;
+ continue;
+ }
+
+ rcu_thread_online();
+
+ LTTNG_ASSERT(msg.cmd == HEALTH_CMD_CHECK);
+
+ memset(&reply, 0, sizeof(reply));
+ for (i = 0; i < NR_HEALTH_CONSUMERD_TYPES; i++) {
+ /*
+ * health_check_state return 0 if thread is in
+ * error.
+ */
+ if (!health_check_state(health_consumerd, i)) {
+ reply.ret_code |= 1ULL << i;
+ }
+ }
+
+ DBG("Health check return value %" PRIx64, reply.ret_code);
+
+ ret = send_unix_sock(new_sock, (void *) &reply, sizeof(reply));
+ if (ret < 0) {
+ ERR("Failed to send health data back to client");
+ }
+
+ /* End of transmission */
+ ret = close(new_sock);
+ if (ret) {
+ PERROR("close");
+ }
+ new_sock = -1;
+ }
+
+exit:
+error:
+ if (err) {
+ ERR("Health error occurred in %s", __func__);
+ }
+ DBG("Health check thread dying");
+ unlink(health_unix_sock_path);
+ if (sock >= 0) {
+ ret = close(sock);
+ if (ret) {
+ PERROR("close");
+ }
+ }
+
+ lttng_poll_clean(&events);
+
+ rcu_unregister_thread();
+ return NULL;
+}