Launch the notification thread using lttng_thread
[lttng-tools.git] / src / bin / lttng-sessiond / main.c
index f9f7646ca05b82ac08b27a77cc2b2e58b58ba8ce..4749f8621b62d1b0512304dcbac6677fd1e79124 100644 (file)
@@ -49,6 +49,9 @@
 #include <common/utils.h>
 #include <common/daemonize.h>
 #include <common/config/session-config.h>
+#include <common/dynamic-buffer.h>
+#include <lttng/userspace-probe-internal.h>
+#include <lttng/event-internal.h>
 
 #include "lttng-sessiond.h"
 #include "buffer-registry.h"
 #include "load-session-thread.h"
 #include "notification-thread.h"
 #include "notification-thread-commands.h"
-#include "syscall.h"
+#include "rotation-thread.h"
+#include "lttng-syscall.h"
 #include "agent.h"
 #include "ht-cleanup.h"
-
-#define CONSUMERD_FILE "lttng-consumerd"
+#include "sessiond-config.h"
+#include "timer.h"
+#include "thread.h"
 
 static const char *help_msg =
 #ifdef LTTNG_EMBED_HELP
@@ -88,30 +93,20 @@ NULL
 ;
 
 const char *progname;
-const char *tracing_group_name = DEFAULT_TRACING_GROUP;
-static int tracing_group_name_override;
-static char *opt_pidfile;
-static int opt_sig_parent;
-static int opt_verbose_consumer;
-static int opt_daemon, opt_background;
-static int opt_no_kernel;
-static char *opt_load_session_path;
-static pid_t ppid;          /* Parent PID for --sig-parent option */
-static pid_t child_ppid;    /* Internal parent PID use with daemonize. */
-static char *rundir;
 static int lockfile_fd = -1;
 
 /* Set to 1 when a SIGUSR1 signal is received. */
 static int recv_child_signal;
 
+static struct lttng_kernel_tracer_version kernel_tracer_version;
+static struct lttng_kernel_tracer_abi_version kernel_tracer_abi_version;
+
 /*
  * Consumer daemon specific control data. Every value not initialized here is
  * set to 0 by the static definition.
  */
 static struct consumer_data kconsumer_data = {
        .type = LTTNG_CONSUMER_KERNEL,
-       .err_unix_sock_path = DEFAULT_KCONSUMERD_ERR_SOCK_PATH,
-       .cmd_unix_sock_path = DEFAULT_KCONSUMERD_CMD_SOCK_PATH,
        .err_sock = -1,
        .cmd_sock = -1,
        .channel_monitor_pipe = -1,
@@ -122,8 +117,6 @@ static struct consumer_data kconsumer_data = {
 };
 static struct consumer_data ustconsumer64_data = {
        .type = LTTNG_CONSUMER64_UST,
-       .err_unix_sock_path = DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH,
-       .cmd_unix_sock_path = DEFAULT_USTCONSUMERD64_CMD_SOCK_PATH,
        .err_sock = -1,
        .cmd_sock = -1,
        .channel_monitor_pipe = -1,
@@ -134,8 +127,6 @@ static struct consumer_data ustconsumer64_data = {
 };
 static struct consumer_data ustconsumer32_data = {
        .type = LTTNG_CONSUMER32_UST,
-       .err_unix_sock_path = DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH,
-       .cmd_unix_sock_path = DEFAULT_USTCONSUMERD32_CMD_SOCK_PATH,
        .err_sock = -1,
        .cmd_sock = -1,
        .channel_monitor_pipe = -1,
@@ -184,26 +175,9 @@ static const char *config_ignore_options[] = { "help", "version", "config" };
 /* Shared between threads */
 static int dispatch_thread_exit;
 
-/* Global application Unix socket path */
-static char apps_unix_sock_path[PATH_MAX];
-/* Global client Unix socket path */
-static char client_unix_sock_path[PATH_MAX];
-/* global wait shm path for UST */
-static char wait_shm_path[PATH_MAX];
-/* Global health check unix path */
-static char health_unix_sock_path[PATH_MAX];
-
 /* Sockets and FDs */
 static int client_sock = -1;
 static int apps_sock = -1;
-int kernel_tracer_fd = -1;
-static int kernel_poll_pipe[2] = { -1, -1 };
-
-/*
- * Quit pipe for all threads. This permits a single cancellation point
- * for all threads when receiving an event on the pipe.
- */
-static int thread_quit_pipe[2] = { -1, -1 };
 
 /*
  * This pipe is used to inform the thread managing application communication
@@ -211,8 +185,6 @@ static int thread_quit_pipe[2] = { -1, -1 };
  */
 static int apps_cmd_pipe[2] = { -1, -1 };
 
-int apps_cmd_notify_pipe[2] = { -1, -1 };
-
 /* Pthread, Mutexes and Semaphores */
 static pthread_t apps_thread;
 static pthread_t apps_notify_thread;
@@ -220,11 +192,10 @@ static pthread_t reg_apps_thread;
 static pthread_t client_thread;
 static pthread_t kernel_thread;
 static pthread_t dispatch_thread;
-static pthread_t health_thread;
-static pthread_t ht_cleanup_thread;
 static pthread_t agent_reg_thread;
 static pthread_t load_session_thread;
-static pthread_t notification_thread;
+static pthread_t rotation_thread;
+static pthread_t timer_thread;
 
 /*
  * UST registration command queue. This queue is tied with a futex and uses a N
@@ -237,30 +208,6 @@ static pthread_t notification_thread;
  */
 static struct ust_cmd_queue ust_cmd_queue;
 
-/*
- * Pointer initialized before thread creation.
- *
- * This points to the tracing session list containing the session count and a
- * mutex lock. The lock MUST be taken if you iterate over the list. The lock
- * MUST NOT be taken if you call a public function in session.c.
- *
- * The lock is nested inside the structure: session_list_ptr->lock. Please use
- * session_lock_list and session_unlock_list for lock acquisition.
- */
-static struct ltt_session_list *session_list_ptr;
-
-int ust_consumerd64_fd = -1;
-int ust_consumerd32_fd = -1;
-
-static const char *consumerd32_bin = CONFIG_CONSUMERD32_BIN;
-static const char *consumerd64_bin = CONFIG_CONSUMERD64_BIN;
-static const char *consumerd32_libdir = CONFIG_CONSUMERD32_LIBDIR;
-static const char *consumerd64_libdir = CONFIG_CONSUMERD64_LIBDIR;
-static int consumerd32_bin_override;
-static int consumerd64_bin_override;
-static int consumerd32_libdir_override;
-static int consumerd64_libdir_override;
-
 static const char *module_proc_lttng = "/proc/lttng";
 
 /*
@@ -297,185 +244,19 @@ enum consumerd_state {
 static enum consumerd_state ust_consumerd_state;
 static enum consumerd_state kernel_consumerd_state;
 
-/*
- * Socket timeout for receiving and sending in seconds.
- */
-static int app_socket_timeout;
-
-/* Set in main() with the current page size. */
-long page_size;
-
-/* Application health monitoring */
-struct health_app *health_sessiond;
-
-/* Agent TCP port for registration. Used by the agent thread. */
-unsigned int agent_tcp_port = DEFAULT_AGENT_TCP_PORT;
-
-/* Am I root or not. */
-int is_root;                   /* Set to 1 if the daemon is running as root */
-
-const char * const config_section_name = "sessiond";
-
 /* Load session thread information to operate. */
-struct load_session_thread_data *load_info;
-
-/* Notification thread handle. */
-struct notification_thread_handle *notification_thread_handle;
-
-/* Global hash tables */
-struct lttng_ht *agent_apps_ht_by_sock = NULL;
-
-/*
- * Whether sessiond is ready for commands/notification channel/health check
- * requests.
- * NR_LTTNG_SESSIOND_READY must match the number of calls to
- * sessiond_notify_ready().
- */
-#define NR_LTTNG_SESSIOND_READY                4
-int lttng_sessiond_ready = NR_LTTNG_SESSIOND_READY;
-
-int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
-{
-       return (fd == thread_quit_pipe[0] && (events & LPOLLIN)) ? 1 : 0;
-}
-
-/* Notify parents that we are ready for cmd and health check */
-LTTNG_HIDDEN
-void sessiond_notify_ready(void)
-{
-       if (uatomic_sub_return(&lttng_sessiond_ready, 1) == 0) {
-               /*
-                * Notify parent pid that we are ready to accept command
-                * for client side.  This ppid is the one from the
-                * external process that spawned us.
-                */
-               if (opt_sig_parent) {
-                       kill(ppid, SIGUSR1);
-               }
-
-               /*
-                * Notify the parent of the fork() process that we are
-                * ready.
-                */
-               if (opt_daemon || opt_background) {
-                       kill(child_ppid, SIGUSR1);
-               }
-       }
-}
-
-static
-void setup_consumerd_path(void)
-{
-       const char *bin, *libdir;
-
-       /*
-        * Allow INSTALL_BIN_PATH to be used as a target path for the
-        * native architecture size consumer if CONFIG_CONSUMER*_PATH
-        * has not been defined.
-        */
-#if (CAA_BITS_PER_LONG == 32)
-       if (!consumerd32_bin[0]) {
-               consumerd32_bin = INSTALL_BIN_PATH "/" CONSUMERD_FILE;
-       }
-       if (!consumerd32_libdir[0]) {
-               consumerd32_libdir = INSTALL_LIB_PATH;
-       }
-#elif (CAA_BITS_PER_LONG == 64)
-       if (!consumerd64_bin[0]) {
-               consumerd64_bin = INSTALL_BIN_PATH "/" CONSUMERD_FILE;
-       }
-       if (!consumerd64_libdir[0]) {
-               consumerd64_libdir = INSTALL_LIB_PATH;
-       }
-#else
-#error "Unknown bitness"
-#endif
-
-       /*
-        * runtime env. var. overrides the build default.
-        */
-       bin = lttng_secure_getenv("LTTNG_CONSUMERD32_BIN");
-       if (bin) {
-               consumerd32_bin = bin;
-       }
-       bin = lttng_secure_getenv("LTTNG_CONSUMERD64_BIN");
-       if (bin) {
-               consumerd64_bin = bin;
-       }
-       libdir = lttng_secure_getenv("LTTNG_CONSUMERD32_LIBDIR");
-       if (libdir) {
-               consumerd32_libdir = libdir;
-       }
-       libdir = lttng_secure_getenv("LTTNG_CONSUMERD64_LIBDIR");
-       if (libdir) {
-               consumerd64_libdir = libdir;
-       }
-}
-
-static
-int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
-               int *a_pipe)
-{
-       int ret;
-
-       assert(events);
-
-       ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
-       if (ret < 0) {
-               goto error;
-       }
-
-       /* Add quit pipe */
-       ret = lttng_poll_add(events, a_pipe[0], LPOLLIN | LPOLLERR);
-       if (ret < 0) {
-               goto error;
-       }
-
-       return 0;
-
-error:
-       return ret;
-}
-
-/*
- * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
- */
-int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)
-{
-       return __sessiond_set_thread_pollset(events, size, thread_quit_pipe);
-}
+static struct load_session_thread_data *load_info;
 
 /*
- * Init thread quit pipe.
- *
- * Return -1 on error or 0 if all pipes are created.
+ * Section name to look for in the daemon configuration file.
  */
-static int __init_thread_quit_pipe(int *a_pipe)
-{
-       int ret, i;
-
-       ret = pipe(a_pipe);
-       if (ret < 0) {
-               PERROR("thread quit pipe");
-               goto error;
-       }
-
-       for (i = 0; i < 2; i++) {
-               ret = fcntl(a_pipe[i], F_SETFD, FD_CLOEXEC);
-               if (ret < 0) {
-                       PERROR("fcntl");
-                       goto error;
-               }
-       }
+static const char * const config_section_name = "sessiond";
 
-error:
-       return ret;
-}
+/* Am I root or not. Set to 1 if the daemon is running as root */
+static int is_root;
 
-static int init_thread_quit_pipe(void)
-{
-       return __init_thread_quit_pipe(thread_quit_pipe);
-}
+/* Rotation thread handle. */
+static struct rotation_thread_handle *rotation_thread_handle;
 
 /*
  * Stop all threads by closing the thread quit pipe.
@@ -486,7 +267,7 @@ static void stop_threads(void)
 
        /* Stopping all threads */
        DBG("Terminating all threads");
-       ret = notify_thread_pipe(thread_quit_pipe[1]);
+       ret = sessiond_notify_quit_pipe();
        if (ret < 0) {
                ERR("write error on thread quit pipe");
        }
@@ -559,27 +340,6 @@ static void close_consumer_sockets(void)
        }
 }
 
-/*
- * Generate the full lock file path using the rundir.
- *
- * Return the snprintf() return value thus a negative value is an error.
- */
-static int generate_lock_file_path(char *path, size_t len)
-{
-       int ret;
-
-       assert(path);
-       assert(rundir);
-
-       /* Build lockfile path from rundir. */
-       ret = snprintf(path, len, "%s/" DEFAULT_LTTNG_SESSIOND_LOCKFILE, rundir);
-       if (ret < 0) {
-               PERROR("snprintf lockfile path");
-       }
-
-       return ret;
-}
-
 /*
  * Wait on consumer process termination.
  *
@@ -613,8 +373,7 @@ static void wait_consumer(struct consumer_data *consumer_data)
 static void sessiond_cleanup(void)
 {
        int ret;
-       struct ltt_session *sess, *stmp;
-       char path[PATH_MAX];
+       struct ltt_session_list *session_list = session_get_list();
 
        DBG("Cleanup sessiond");
 
@@ -622,84 +381,45 @@ static void sessiond_cleanup(void)
         * Close the thread quit pipe. It has already done its job,
         * since we are now called.
         */
-       utils_close_pipe(thread_quit_pipe);
+       sessiond_close_quit_pipe();
 
-       /*
-        * If opt_pidfile is undefined, the default file will be wiped when
-        * removing the rundir.
-        */
-       if (opt_pidfile) {
-               ret = remove(opt_pidfile);
-               if (ret < 0) {
-                       PERROR("remove pidfile %s", opt_pidfile);
-               }
+       ret = remove(config.pid_file_path.value);
+       if (ret < 0) {
+               PERROR("remove pidfile %s", config.pid_file_path.value);
        }
 
-       DBG("Removing sessiond and consumerd content of directory %s", rundir);
+       DBG("Removing sessiond and consumerd content of directory %s",
+               config.rundir.value);
 
        /* sessiond */
-       snprintf(path, PATH_MAX,
-               "%s/%s",
-               rundir, DEFAULT_LTTNG_SESSIOND_PIDFILE);
-       DBG("Removing %s", path);
-       (void) unlink(path);
+       DBG("Removing %s", config.pid_file_path.value);
+       (void) unlink(config.pid_file_path.value);
 
-       snprintf(path, PATH_MAX, "%s/%s", rundir,
-                       DEFAULT_LTTNG_SESSIOND_AGENTPORT_FILE);
-       DBG("Removing %s", path);
-       (void) unlink(path);
+       DBG("Removing %s", config.agent_port_file_path.value);
+       (void) unlink(config.agent_port_file_path.value);
 
        /* kconsumerd */
-       snprintf(path, PATH_MAX,
-               DEFAULT_KCONSUMERD_ERR_SOCK_PATH,
-               rundir);
-       DBG("Removing %s", path);
-       (void) unlink(path);
-
-       snprintf(path, PATH_MAX,
-               DEFAULT_KCONSUMERD_PATH,
-               rundir);
-       DBG("Removing directory %s", path);
-       (void) rmdir(path);
+       DBG("Removing %s", kconsumer_data.err_unix_sock_path);
+       (void) unlink(kconsumer_data.err_unix_sock_path);
 
-       /* ust consumerd 32 */
-       snprintf(path, PATH_MAX,
-               DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH,
-               rundir);
-       DBG("Removing %s", path);
-       (void) unlink(path);
-
-       snprintf(path, PATH_MAX,
-               DEFAULT_USTCONSUMERD32_PATH,
-               rundir);
-       DBG("Removing directory %s", path);
-       (void) rmdir(path);
+       DBG("Removing directory %s", config.kconsumerd_path.value);
+       (void) rmdir(config.kconsumerd_path.value);
 
-       /* ust consumerd 64 */
-       snprintf(path, PATH_MAX,
-               DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH,
-               rundir);
-       DBG("Removing %s", path);
-       (void) unlink(path);
+       /* ust consumerd 32 */
+       DBG("Removing %s", config.consumerd32_err_unix_sock_path.value);
+       (void) unlink(config.consumerd32_err_unix_sock_path.value);
 
-       snprintf(path, PATH_MAX,
-               DEFAULT_USTCONSUMERD64_PATH,
-               rundir);
-       DBG("Removing directory %s", path);
-       (void) rmdir(path);
+       DBG("Removing directory %s", config.consumerd32_path.value);
+       (void) rmdir(config.consumerd32_path.value);
 
-       DBG("Cleaning up all sessions");
+       /* ust consumerd 64 */
+       DBG("Removing %s", config.consumerd64_err_unix_sock_path.value);
+       (void) unlink(config.consumerd64_err_unix_sock_path.value);
 
-       /* Destroy session list mutex */
-       if (session_list_ptr != NULL) {
-               pthread_mutex_destroy(&session_list_ptr->lock);
+       DBG("Removing directory %s", config.consumerd64_path.value);
+       (void) rmdir(config.consumerd64_path.value);
 
-               /* Cleanup ALL session */
-               cds_list_for_each_entry_safe(sess, stmp,
-                               &session_list_ptr->head, list) {
-                       cmd_destroy_session(sess, kernel_poll_pipe[1]);
-               }
-       }
+       pthread_mutex_destroy(&session_list->lock);
 
        wait_consumer(&kconsumer_data);
        wait_consumer(&ustconsumer64_data);
@@ -712,7 +432,7 @@ static void sessiond_cleanup(void)
        ust_app_clean_list();
        buffer_reg_destroy_registries();
 
-       if (is_root && !opt_no_kernel) {
+       if (is_root && !config.no_kernel) {
                DBG2("Closing kernel fd");
                if (kernel_tracer_fd >= 0) {
                        ret = close(kernel_tracer_fd);
@@ -732,34 +452,11 @@ static void sessiond_cleanup(void)
                free(load_info);
        }
 
-       /*
-        * Cleanup lock file by deleting it and finaly closing it which will
-        * release the file system lock.
-        */
-       if (lockfile_fd >= 0) {
-               char lockfile_path[PATH_MAX];
-
-               ret = generate_lock_file_path(lockfile_path,
-                               sizeof(lockfile_path));
-               if (ret > 0) {
-                       ret = remove(lockfile_path);
-                       if (ret < 0) {
-                               PERROR("remove lock file");
-                       }
-                       ret = close(lockfile_fd);
-                       if (ret < 0) {
-                               PERROR("close lock file");
-                       }
-               }
-       }
-
        /*
         * We do NOT rmdir rundir because there are other processes
         * using it, for instance lttng-relayd, which can start in
         * parallel with this teardown.
         */
-
-       free(rundir);
 }
 
 /*
@@ -769,30 +466,7 @@ static void sessiond_cleanup_options(void)
 {
        DBG("Cleaning up options");
 
-       /*
-        * If the override option is set, the pointer points to a *non* const
-        * thus freeing it even though the variable type is set to const.
-        */
-       if (tracing_group_name_override) {
-               free((void *) tracing_group_name);
-       }
-       if (consumerd32_bin_override) {
-               free((void *) consumerd32_bin);
-       }
-       if (consumerd64_bin_override) {
-               free((void *) consumerd64_bin);
-       }
-       if (consumerd32_libdir_override) {
-               free((void *) consumerd32_libdir);
-       }
-       if (consumerd64_libdir_override) {
-               free((void *) consumerd64_libdir);
-       }
-
-       free(opt_pidfile);
-       free(opt_load_session_path);
-       free(kmod_probes_list);
-       free(kmod_extra_probes_list);
+       sessiond_config_fini(&config);
 
        run_as_destroy_worker();
 }
@@ -840,7 +514,7 @@ static int notify_ust_apps(int active)
        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(wait_shm_path, is_root);
+       wait_shm_mmap = shm_ust_get_mmap(config.wait_shm_path.value, is_root);
        if (wait_shm_mmap == NULL) {
                goto error;
        }
@@ -918,16 +592,21 @@ static int setup_lttng_msg_no_cmd_header(struct command_ctx *cmd_ctx,
 static int update_kernel_poll(struct lttng_poll_event *events)
 {
        int ret;
-       struct ltt_session *session;
        struct ltt_kernel_channel *channel;
+       struct ltt_session *session;
+       const struct ltt_session_list *session_list = session_get_list();
 
        DBG("Updating kernel poll set");
 
        session_lock_list();
-       cds_list_for_each_entry(session, &session_list_ptr->head, list) {
+       cds_list_for_each_entry(session, &session_list->head, list) {
+               if (!session_get(session)) {
+                       continue;
+               }
                session_lock(session);
                if (session->kernel_session == NULL) {
                        session_unlock(session);
+                       session_put(session);
                        continue;
                }
 
@@ -937,6 +616,7 @@ static int update_kernel_poll(struct lttng_poll_event *events)
                        ret = lttng_poll_add(events, channel->fd, LPOLLIN | LPOLLRDNORM);
                        if (ret < 0) {
                                session_unlock(session);
+                               session_put(session);
                                goto error;
                        }
                        DBG("Channel fd %d added to kernel set", channel->fd);
@@ -958,20 +638,25 @@ error:
  *
  * Useful for CPU hotplug feature.
  */
-static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
+static int update_kernel_stream(int fd)
 {
        int ret = 0;
        struct ltt_session *session;
        struct ltt_kernel_session *ksess;
        struct ltt_kernel_channel *channel;
+       const struct ltt_session_list *session_list = session_get_list();
 
        DBG("Updating kernel streams for channel fd %d", fd);
 
        session_lock_list();
-       cds_list_for_each_entry(session, &session_list_ptr->head, list) {
+       cds_list_for_each_entry(session, &session_list->head, list) {
+               if (!session_get(session)) {
+                       continue;
+               }
                session_lock(session);
                if (session->kernel_session == NULL) {
                        session_unlock(session);
+                       session_put(session);
                        continue;
                }
                ksess = session->kernel_session;
@@ -1007,7 +692,7 @@ static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
                        cds_lfht_for_each_entry(ksess->consumer->socks->ht,
                                        &iter.iter, socket, node.node) {
                                pthread_mutex_lock(socket->lock);
-                               ret = kernel_consumer_send_channel_stream(socket,
+                               ret = kernel_consumer_send_channel_streams(socket,
                                                channel, ksess,
                                                session->output_traces ? 1 : 0);
                                pthread_mutex_unlock(socket->lock);
@@ -1019,12 +704,14 @@ static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
                        rcu_read_unlock();
                }
                session_unlock(session);
+               session_put(session);
        }
        session_unlock_list();
        return ret;
 
 error:
        session_unlock(session);
+       session_put(session);
        session_unlock_list();
        return ret;
 }
@@ -1036,6 +723,7 @@ error:
 static void update_ust_app(int app_sock)
 {
        struct ltt_session *sess, *stmp;
+       const struct ltt_session_list *session_list = session_get_list();
 
        /* Consumer is in an ERROR state. Stop any application update. */
        if (uatomic_read(&ust_consumerd_state) == CONSUMER_ERROR) {
@@ -1044,9 +732,12 @@ static void update_ust_app(int app_sock)
        }
 
        /* For all tracing session(s) */
-       cds_list_for_each_entry_safe(sess, stmp, &session_list_ptr->head, list) {
+       cds_list_for_each_entry_safe(sess, stmp, &session_list->head, list) {
                struct ust_app *app;
 
+               if (!session_get(sess)) {
+                       continue;
+               }
                session_lock(sess);
                if (!sess->ust_session) {
                        goto unlock_session;
@@ -1070,6 +761,7 @@ static void update_ust_app(int app_sock)
                rcu_read_unlock();
        unlock_session:
                session_unlock(sess);
+               session_put(sess);
        }
 }
 
@@ -1192,7 +884,7 @@ static void *thread_manage_kernel(void *data)
                                         * New CPU detected by the kernel. Adding kernel stream to
                                         * kernel session and updating the kernel consumer
                                         */
-                                       ret = update_kernel_stream(&kconsumer_data, pollfd);
+                                       ret = update_kernel_stream(pollfd);
                                        if (ret < 0) {
                                                continue;
                                        }
@@ -1427,19 +1119,21 @@ restart:
        health_code_update();
 
        /*
-        * Transfer the write-end of the channel monitoring pipe to the
-        * by issuing a SET_CHANNEL_MONITOR_PIPE command.
+        * Transfer the write-end of the channel monitoring and rotate pipe
+        * to the consumer by issuing a SET_CHANNEL_MONITOR_PIPE command.
         */
        cmd_socket_wrapper = consumer_allocate_socket(&consumer_data->cmd_sock);
        if (!cmd_socket_wrapper) {
                goto error;
        }
+       cmd_socket_wrapper->lock = &consumer_data->lock;
 
        ret = consumer_send_channel_monitor_pipe(cmd_socket_wrapper,
                        consumer_data->channel_monitor_pipe);
        if (ret) {
                goto error;
        }
+
        /* Discard the socket wrapper as it is no longer needed. */
        consumer_destroy_socket(cmd_socket_wrapper);
        cmd_socket_wrapper = NULL;
@@ -1609,7 +1303,17 @@ error_poll:
 }
 
 /*
- * This thread manage application communication.
+ * This thread receives application command sockets (FDs) on the
+ * apps_cmd_pipe and waits (polls) on them until they are closed
+ * or an error occurs.
+ *
+ * At that point, it flushes the data (tracing and metadata) associated
+ * with this application and tears down ust app sessions and other
+ * associated data structures through ust_app_unregister().
+ *
+ * Note that this thread never sends commands to the applications
+ * through the command sockets; it merely listens for hang-ups
+ * and errors on those sockets and cleans-up as they occur.
  */
 static void *thread_manage_apps(void *data)
 {
@@ -2267,11 +1971,11 @@ static void *thread_registration_apps(void *data)
                                         * lttcomm_setsockopt_snd_timeout expect msec as
                                         * parameter.
                                         */
-                                       if (app_socket_timeout >= 0) {
+                                       if (config.app_socket_timeout >= 0) {
                                                (void) lttcomm_setsockopt_rcv_timeout(sock,
-                                                               app_socket_timeout * 1000);
+                                                               config.app_socket_timeout * 1000);
                                                (void) lttcomm_setsockopt_snd_timeout(sock,
-                                                               app_socket_timeout * 1000);
+                                                               config.app_socket_timeout * 1000);
                                        }
 
                                        /*
@@ -2372,7 +2076,7 @@ error:
                }
                lttng_fd_put(LTTNG_FD_APPS, 1);
        }
-       unlink(apps_unix_sock_path);
+       unlink(config.apps_unix_sock_path.value);
 
 error_poll_add:
        lttng_poll_clean(&events);
@@ -2561,7 +2265,7 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                /*
                 * Exec consumerd.
                 */
-               if (opt_verbose_consumer) {
+               if (config.verbose_consumer) {
                        verbosity = "--verbose";
                } else if (lttng_opt_quiet) {
                        verbosity = "--quiet";
@@ -2577,120 +2281,109 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                         * fallback on the 32-bit one,
                         */
                        DBG3("Looking for a kernel consumer at these locations:");
-                       DBG3("  1) %s", consumerd64_bin);
-                       DBG3("  2) %s/%s", INSTALL_BIN_PATH, CONSUMERD_FILE);
-                       DBG3("  3) %s", consumerd32_bin);
-                       if (stat(consumerd64_bin, &st) == 0) {
+                       DBG3("  1) %s", config.consumerd64_bin_path.value ? : "NULL");
+                       DBG3("  2) %s/%s", INSTALL_BIN_PATH, DEFAULT_CONSUMERD_FILE);
+                       DBG3("  3) %s", config.consumerd32_bin_path.value ? : "NULL");
+                       if (stat(config.consumerd64_bin_path.value, &st) == 0) {
                                DBG3("Found location #1");
-                               consumer_to_use = consumerd64_bin;
-                       } else if (stat(INSTALL_BIN_PATH "/" CONSUMERD_FILE, &st) == 0) {
+                               consumer_to_use = config.consumerd64_bin_path.value;
+                       } else if (stat(INSTALL_BIN_PATH "/" DEFAULT_CONSUMERD_FILE, &st) == 0) {
                                DBG3("Found location #2");
-                               consumer_to_use = INSTALL_BIN_PATH "/" CONSUMERD_FILE;
-                       } else if (stat(consumerd32_bin, &st) == 0) {
+                               consumer_to_use = INSTALL_BIN_PATH "/" DEFAULT_CONSUMERD_FILE;
+                       } else if (config.consumerd32_bin_path.value &&
+                                       stat(config.consumerd32_bin_path.value, &st) == 0) {
                                DBG3("Found location #3");
-                               consumer_to_use = consumerd32_bin;
+                               consumer_to_use = config.consumerd32_bin_path.value;
                        } else {
                                DBG("Could not find any valid consumerd executable");
                                ret = -EINVAL;
-                               break;
+                               goto error;
                        }
                        DBG("Using kernel consumer at: %s",  consumer_to_use);
-                       ret = execl(consumer_to_use,
+                       (void) execl(consumer_to_use,
                                "lttng-consumerd", verbosity, "-k",
                                "--consumerd-cmd-sock", consumer_data->cmd_unix_sock_path,
                                "--consumerd-err-sock", consumer_data->err_unix_sock_path,
-                               "--group", tracing_group_name,
+                               "--group", config.tracing_group_name.value,
                                NULL);
                        break;
                case LTTNG_CONSUMER64_UST:
                {
-                       char *tmpnew = NULL;
-
-                       if (consumerd64_libdir[0] != '\0') {
+                       if (config.consumerd64_lib_dir.value) {
                                char *tmp;
                                size_t tmplen;
+                               char *tmpnew;
 
                                tmp = lttng_secure_getenv("LD_LIBRARY_PATH");
                                if (!tmp) {
                                        tmp = "";
                                }
-                               tmplen = strlen("LD_LIBRARY_PATH=")
-                                       + strlen(consumerd64_libdir) + 1 /* : */ + strlen(tmp);
+                               tmplen = strlen(config.consumerd64_lib_dir.value) + 1 /* : */ + strlen(tmp);
                                tmpnew = zmalloc(tmplen + 1 /* \0 */);
                                if (!tmpnew) {
                                        ret = -ENOMEM;
                                        goto error;
                                }
-                               strcpy(tmpnew, "LD_LIBRARY_PATH=");
-                               strcat(tmpnew, consumerd64_libdir);
+                               strcat(tmpnew, config.consumerd64_lib_dir.value);
                                if (tmp[0] != '\0') {
                                        strcat(tmpnew, ":");
                                        strcat(tmpnew, tmp);
                                }
-                               ret = putenv(tmpnew);
+                               ret = setenv("LD_LIBRARY_PATH", tmpnew, 1);
+                               free(tmpnew);
                                if (ret) {
                                        ret = -errno;
-                                       free(tmpnew);
                                        goto error;
                                }
                        }
-                       DBG("Using 64-bit UST consumer at: %s",  consumerd64_bin);
-                       ret = execl(consumerd64_bin, "lttng-consumerd", verbosity, "-u",
+                       DBG("Using 64-bit UST consumer at: %s",  config.consumerd64_bin_path.value);
+                       (void) execl(config.consumerd64_bin_path.value, "lttng-consumerd", verbosity, "-u",
                                        "--consumerd-cmd-sock", consumer_data->cmd_unix_sock_path,
                                        "--consumerd-err-sock", consumer_data->err_unix_sock_path,
-                                       "--group", tracing_group_name,
+                                       "--group", config.tracing_group_name.value,
                                        NULL);
-                       if (consumerd64_libdir[0] != '\0') {
-                               free(tmpnew);
-                       }
                        break;
                }
                case LTTNG_CONSUMER32_UST:
                {
-                       char *tmpnew = NULL;
-
-                       if (consumerd32_libdir[0] != '\0') {
+                       if (config.consumerd32_lib_dir.value) {
                                char *tmp;
                                size_t tmplen;
+                               char *tmpnew;
 
                                tmp = lttng_secure_getenv("LD_LIBRARY_PATH");
                                if (!tmp) {
                                        tmp = "";
                                }
-                               tmplen = strlen("LD_LIBRARY_PATH=")
-                                       + strlen(consumerd32_libdir) + 1 /* : */ + strlen(tmp);
+                               tmplen = strlen(config.consumerd32_lib_dir.value) + 1 /* : */ + strlen(tmp);
                                tmpnew = zmalloc(tmplen + 1 /* \0 */);
                                if (!tmpnew) {
                                        ret = -ENOMEM;
                                        goto error;
                                }
-                               strcpy(tmpnew, "LD_LIBRARY_PATH=");
-                               strcat(tmpnew, consumerd32_libdir);
+                               strcat(tmpnew, config.consumerd32_lib_dir.value);
                                if (tmp[0] != '\0') {
                                        strcat(tmpnew, ":");
                                        strcat(tmpnew, tmp);
                                }
-                               ret = putenv(tmpnew);
+                               ret = setenv("LD_LIBRARY_PATH", tmpnew, 1);
+                               free(tmpnew);
                                if (ret) {
                                        ret = -errno;
-                                       free(tmpnew);
                                        goto error;
                                }
                        }
-                       DBG("Using 32-bit UST consumer at: %s",  consumerd32_bin);
-                       ret = execl(consumerd32_bin, "lttng-consumerd", verbosity, "-u",
+                       DBG("Using 32-bit UST consumer at: %s",  config.consumerd32_bin_path.value);
+                       (void) execl(config.consumerd32_bin_path.value, "lttng-consumerd", verbosity, "-u",
                                        "--consumerd-cmd-sock", consumer_data->cmd_unix_sock_path,
                                        "--consumerd-err-sock", consumer_data->err_unix_sock_path,
-                                       "--group", tracing_group_name,
+                                       "--group", config.tracing_group_name.value,
                                        NULL);
-                       if (consumerd32_libdir[0] != '\0') {
-                               free(tmpnew);
-                       }
                        break;
                }
                default:
-                       PERROR("unknown consumer type");
-                       exit(EXIT_FAILURE);
+                       ERR("unknown consumer type");
+                       errno = 0;
                }
                if (errno != 0) {
                        PERROR("Consumer execl()");
@@ -2782,12 +2475,12 @@ static int init_kernel_tracer(void)
        kernel_tracer_fd = open(module_proc_lttng, O_RDWR);
        if (kernel_tracer_fd < 0) {
                DBG("Failed to open %s", module_proc_lttng);
-               ret = -1;
                goto error_open;
        }
 
        /* Validate kernel version */
-       ret = kernel_validate_version(kernel_tracer_fd);
+       ret = kernel_validate_version(kernel_tracer_fd, &kernel_tracer_version,
+                       &kernel_tracer_abi_version);
        if (ret < 0) {
                goto error_version;
        }
@@ -2994,20 +2687,6 @@ static int create_kernel_session(struct ltt_session *session)
                goto error;
        }
 
-       /* Create directory(ies) on local filesystem. */
-       if (session->kernel_session->consumer->type == CONSUMER_DST_LOCAL &&
-                       strlen(session->kernel_session->consumer->dst.trace_path) > 0) {
-               ret = run_as_mkdir_recursive(
-                               session->kernel_session->consumer->dst.trace_path,
-                               S_IRWXU | S_IRWXG, session->uid, session->gid);
-               if (ret < 0) {
-                       if (errno != EEXIST) {
-                               ERR("Trace directory creation error");
-                               goto error;
-                       }
-               }
-       }
-
        session->kernel_session->uid = session->uid;
        session->kernel_session->gid = session->gid;
        session->kernel_session->output_traces = session->output_traces;
@@ -3028,21 +2707,148 @@ static unsigned int lttng_sessions_count(uid_t uid, gid_t gid)
 {
        unsigned int i = 0;
        struct ltt_session *session;
+       const struct ltt_session_list *session_list = session_get_list();
 
        DBG("Counting number of available session for UID %d GID %d",
                        uid, gid);
-       cds_list_for_each_entry(session, &session_list_ptr->head, list) {
-               /*
-                * Only list the sessions the user can control.
-                */
-               if (!session_access_ok(session, uid, gid)) {
+       cds_list_for_each_entry(session, &session_list->head, list) {
+               if (!session_get(session)) {
                        continue;
                }
-               i++;
+               session_lock(session);
+               /* Only count the sessions the user can control. */
+               if (session_access_ok(session, uid, gid) &&
+                               !session->destroyed) {
+                       i++;
+               }
+               session_unlock(session);
+               session_put(session);
        }
        return i;
 }
 
+static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
+               int *sock_error, struct lttng_event *event)
+{
+       int fd, ret;
+       struct lttng_userspace_probe_location *probe_location;
+       const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
+       struct lttng_dynamic_buffer probe_location_buffer;
+       struct lttng_buffer_view buffer_view;
+
+       /*
+        * Create a buffer to store the serialized version of the probe
+        * location.
+        */
+       lttng_dynamic_buffer_init(&probe_location_buffer);
+       ret = lttng_dynamic_buffer_set_size(&probe_location_buffer,
+                       cmd_ctx->lsm->u.enable.userspace_probe_location_len);
+       if (ret) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       /*
+        * Receive the probe location.
+        */
+       ret = lttcomm_recv_unix_sock(sock, probe_location_buffer.data,
+                       probe_location_buffer.size);
+       if (ret <= 0) {
+               DBG("Nothing recv() from client var len data... continuing");
+               *sock_error = 1;
+               lttng_dynamic_buffer_reset(&probe_location_buffer);
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       buffer_view = lttng_buffer_view_from_dynamic_buffer(
+                       &probe_location_buffer, 0, probe_location_buffer.size);
+
+       /*
+        * Extract the probe location from the serialized version.
+        */
+       ret = lttng_userspace_probe_location_create_from_buffer(
+                               &buffer_view, &probe_location);
+       if (ret < 0) {
+               WARN("Failed to create a userspace probe location from the received buffer");
+               lttng_dynamic_buffer_reset( &probe_location_buffer);
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /*
+        * Receive the file descriptor to the target binary from the client.
+        */
+       DBG("Receiving userspace probe target FD from client ...");
+       ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
+       if (ret <= 0) {
+               DBG("Nothing recv() from client userspace probe fd... continuing");
+               *sock_error = 1;
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /*
+        * Set the file descriptor received from the client through the unix
+        * socket in the probe location.
+        */
+       lookup = lttng_userspace_probe_location_get_lookup_method(probe_location);
+       if (!lookup) {
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /*
+        * From the kernel tracer's perspective, all userspace probe event types
+        * are all the same: a file and an offset.
+        */
+       switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
+       case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
+               ret = lttng_userspace_probe_location_function_set_binary_fd(
+                               probe_location, fd);
+               break;
+       case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
+               ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
+                               probe_location, fd);
+               break;
+       default:
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       if (ret) {
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /* Attach the probe location to the event. */
+       ret = lttng_event_set_userspace_probe_location(event, probe_location);
+       if (ret) {
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       lttng_dynamic_buffer_reset(&probe_location_buffer);
+error:
+       return ret;
+}
+
+/*
+ * Check if the current kernel tracer supports the session rotation feature.
+ * Return 1 if it does, 0 otherwise.
+ */
+static int check_rotate_compatible(void)
+{
+       int ret = 1;
+
+       if (kernel_tracer_version.major != 2 || kernel_tracer_version.minor < 11) {
+               DBG("Kernel tracer version is not compatible with the rotation feature");
+               ret = 0;
+       }
+
+       return ret;
+}
+
 /*
  * Process the command requested by the lttng client within the command
  * context structure. This function make sure that the return structure (llm)
@@ -3087,13 +2893,17 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_REGENERATE_STATEDUMP:
        case LTTNG_REGISTER_TRIGGER:
        case LTTNG_UNREGISTER_TRIGGER:
+       case LTTNG_ROTATE_SESSION:
+       case LTTNG_ROTATION_GET_INFO:
+       case LTTNG_ROTATION_SET_SCHEDULE:
+       case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
                need_domain = 0;
                break;
        default:
                need_domain = 1;
        }
 
-       if (opt_no_kernel && need_domain
+       if (config.no_kernel && need_domain
                        && cmd_ctx->lsm->domain.type == LTTNG_DOMAIN_KERNEL) {
                if (!is_root) {
                        ret = LTTNG_ERR_NEED_ROOT_SESSIOND;
@@ -3129,6 +2939,9 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_LIST_SYSCALLS:
        case LTTNG_LIST_TRACKER_PIDS:
        case LTTNG_DATA_PENDING:
+       case LTTNG_ROTATE_SESSION:
+       case LTTNG_ROTATION_GET_INFO:
+       case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
                break;
        default:
                /* Setup lttng message with no payload */
@@ -3299,7 +3112,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                        /* Start the UST consumer daemons */
                        /* 64-bit */
                        pthread_mutex_lock(&ustconsumer64_data.pid_mutex);
-                       if (consumerd64_bin[0] != '\0' &&
+                       if (config.consumerd64_bin_path.value &&
                                        ustconsumer64_data.pid == 0 &&
                                        cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
                                pthread_mutex_unlock(&ustconsumer64_data.pid_mutex);
@@ -3328,7 +3141,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
 
                        /* 32-bit */
                        pthread_mutex_lock(&ustconsumer32_data.pid_mutex);
-                       if (consumerd32_bin[0] != '\0' &&
+                       if (config.consumerd32_bin_path.value &&
                                        ustconsumer32_data.pid == 0 &&
                                        cmd_ctx->lsm->cmd_type != LTTNG_REGISTER_CONSUMER) {
                                pthread_mutex_unlock(&ustconsumer32_data.pid_mutex);
@@ -3346,7 +3159,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                        }
 
                        /*
-                        * Setup socket for consumer 64 bit. No need for atomic access
+                        * Setup socket for consumer 32 bit. No need for atomic access
                         * since it was set above and can ONLY be set in this thread.
                         */
                        ret = consumer_create_socket(&ustconsumer32_data,
@@ -3396,7 +3209,8 @@ skip_domain:
        if (need_tracing_session) {
                if (!session_access_ok(cmd_ctx->session,
                                LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
-                               LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds))) {
+                               LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds)) ||
+                               cmd_ctx->session->destroyed) {
                        ret = LTTNG_ERR_EPERM;
                        goto error;
                }
@@ -3557,6 +3371,7 @@ error_add_context:
        }
        case LTTNG_ENABLE_EVENT:
        {
+               struct lttng_event *ev = NULL;
                struct lttng_event_exclusion *exclusion = NULL;
                struct lttng_filter_bytecode *bytecode = NULL;
                char *filter_expression = NULL;
@@ -3608,7 +3423,7 @@ error_add_context:
                        ret = lttcomm_recv_unix_sock(sock, filter_expression,
                                expression_len);
                        if (ret <= 0) {
-                               DBG("Nothing recv() from client car len data... continuing");
+                               DBG("Nothing recv() from client var len data... continuing");
                                *sock_error = 1;
                                free(filter_expression);
                                free(exclusion);
@@ -3640,7 +3455,7 @@ error_add_context:
                        DBG("Receiving var len filter's bytecode from client ...");
                        ret = lttcomm_recv_unix_sock(sock, bytecode, bytecode_len);
                        if (ret <= 0) {
-                               DBG("Nothing recv() from client car len data... continuing");
+                               DBG("Nothing recv() from client var len data... continuing");
                                *sock_error = 1;
                                free(filter_expression);
                                free(bytecode);
@@ -3658,17 +3473,42 @@ error_add_context:
                        }
                }
 
-               ret = cmd_enable_event(cmd_ctx->session, &cmd_ctx->lsm->domain,
-                               cmd_ctx->lsm->u.enable.channel_name,
-                               &cmd_ctx->lsm->u.enable.event,
-                               filter_expression, bytecode, exclusion,
-                               kernel_poll_pipe[1]);
-               break;
-       }
-       case LTTNG_LIST_TRACEPOINTS:
-       {
-               struct lttng_event *events;
-               ssize_t nb_events;
+               ev = lttng_event_copy(&cmd_ctx->lsm->u.enable.event);
+               if (!ev) {
+                       DBG("Failed to copy event: %s",
+                                       cmd_ctx->lsm->u.enable.event.name);
+                       free(filter_expression);
+                       free(bytecode);
+                       free(exclusion);
+                       ret = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+
+
+               if (cmd_ctx->lsm->u.enable.userspace_probe_location_len > 0) {
+                       /* Expect a userspace probe description. */
+                       ret = receive_userspace_probe(cmd_ctx, sock, sock_error, ev);
+                       if (ret) {
+                               free(filter_expression);
+                               free(bytecode);
+                               free(exclusion);
+                               lttng_event_destroy(ev);
+                               goto error;
+                       }
+               }
+
+               ret = cmd_enable_event(cmd_ctx->session, &cmd_ctx->lsm->domain,
+                               cmd_ctx->lsm->u.enable.channel_name,
+                               ev,
+                               filter_expression, bytecode, exclusion,
+                               kernel_poll_pipe[1]);
+               lttng_event_destroy(ev);
+               break;
+       }
+       case LTTNG_LIST_TRACEPOINTS:
+       {
+               struct lttng_event *events;
+               ssize_t nb_events;
 
                session_lock_list();
                nb_events = cmd_list_tracepoints(cmd_ctx->lsm->domain.type, &events);
@@ -3820,6 +3660,20 @@ error_add_context:
        }
        case LTTNG_START_TRACE:
        {
+               /*
+                * On the first start, if we have a kernel session and we have
+                * enabled time or size-based rotations, we have to make sure
+                * the kernel tracer supports it.
+                */
+               if (!cmd_ctx->session->has_been_started && \
+                               cmd_ctx->session->kernel_session && \
+                               (cmd_ctx->session->rotate_timer_period || \
+                                       cmd_ctx->session->rotate_size) && \
+                               !check_rotate_compatible()) {
+                       DBG("Kernel tracer version is not compatible with the rotation feature");
+                       ret = LTTNG_ERR_ROTATION_WRONG_VERSION;
+                       goto error;
+               }
                ret = cmd_start_trace(cmd_ctx->session);
                break;
        }
@@ -3871,10 +3725,8 @@ error_add_context:
        }
        case LTTNG_DESTROY_SESSION:
        {
-               ret = cmd_destroy_session(cmd_ctx->session, kernel_poll_pipe[1]);
-
-               /* Set session to NULL so we do not unlock it after free. */
-               cmd_ctx->session = NULL;
+               ret = cmd_destroy_session(cmd_ctx->session,
+                               notification_thread_handle);
                break;
        }
        case LTTNG_LIST_DOMAINS:
@@ -4217,220 +4069,128 @@ error_add_context:
                                notification_thread_handle);
                break;
        }
-       default:
-               ret = LTTNG_ERR_UND;
-               break;
-       }
-
-error:
-       if (cmd_ctx->llm == NULL) {
-               DBG("Missing llm structure. Allocating one.");
-               if (setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0) < 0) {
-                       goto setup_error;
-               }
-       }
-       /* Set return code */
-       cmd_ctx->llm->ret_code = ret;
-setup_error:
-       if (cmd_ctx->session) {
-               session_unlock(cmd_ctx->session);
-       }
-       if (need_tracing_session) {
-               session_unlock_list();
-       }
-init_setup_error:
-       assert(!rcu_read_ongoing());
-       return ret;
-}
-
-/*
- * Thread managing health check socket.
- */
-static 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;
-
-       DBG("[thread] Manage health check started");
-
-       rcu_register_thread();
+       case LTTNG_ROTATE_SESSION:
+       {
+               struct lttng_rotate_session_return rotate_return;
 
-       /* We might hit an error path before this is created. */
-       lttng_poll_init(&events);
+               DBG("Client rotate session \"%s\"", cmd_ctx->session->name);
 
-       /* Create unix socket */
-       sock = lttcomm_create_unix_sock(health_unix_sock_path);
-       if (sock < 0) {
-               ERR("Unable to create health check Unix socket");
-               goto error;
-       }
+               memset(&rotate_return, 0, sizeof(rotate_return));
+               if (cmd_ctx->session->kernel_session && !check_rotate_compatible()) {
+                       DBG("Kernel tracer version is not compatible with the rotation feature");
+                       ret = LTTNG_ERR_ROTATION_WRONG_VERSION;
+                       goto error;
+               }
 
-       if (is_root) {
-               /* lttng health client socket path permissions */
-               ret = chown(health_unix_sock_path, 0,
-                               utils_get_group_id(tracing_group_name));
+               ret = cmd_rotate_session(cmd_ctx->session, &rotate_return);
                if (ret < 0) {
-                       ERR("Unable to set group on %s", health_unix_sock_path);
-                       PERROR("chown");
+                       ret = -ret;
                        goto error;
                }
 
-               ret = chmod(health_unix_sock_path,
-                               S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, &rotate_return,
+                               sizeof(rotate_return));
                if (ret < 0) {
-                       ERR("Unable to set permissions on %s", health_unix_sock_path);
-                       PERROR("chmod");
+                       ret = -ret;
                        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;
-       }
-
-       /*
-        * Pass 2 as size here for the thread quit pipe and client_sock. Nothing
-        * more will be added to this poll set.
-        */
-       ret = sessiond_set_thread_pollset(&events, 2);
-       if (ret < 0) {
-               goto error;
-       }
 
-       /* Add the application registration socket */
-       ret = lttng_poll_add(&events, sock, LPOLLIN | LPOLLPRI);
-       if (ret < 0) {
-               goto error;
+               ret = LTTNG_OK;
+               break;
        }
+       case LTTNG_ROTATION_GET_INFO:
+       {
+               struct lttng_rotation_get_info_return get_info_return;
 
-       sessiond_notify_ready();
-
-       while (1) {
-               DBG("Health check ready");
-
-               /* Inifinite blocking call, waiting for transmission */
-restart:
-               ret = lttng_poll_wait(&events, -1);
+               memset(&get_info_return, 0, sizeof(get_info_return));
+               ret = cmd_rotate_get_info(cmd_ctx->session, &get_info_return,
+                               cmd_ctx->lsm->u.get_rotation_info.rotation_id);
                if (ret < 0) {
-                       /*
-                        * Restart interrupted system call.
-                        */
-                       if (errno == EINTR) {
-                               goto restart;
-                       }
+                       ret = -ret;
                        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);
-
-                       if (!revents) {
-                               /* No activity for this FD (poll implementation). */
-                               continue;
-                       }
-
-                       /* Thread quit pipe has been closed. Killing thread. */
-                       ret = sessiond_check_thread_quit_pipe(pollfd, revents);
-                       if (ret) {
-                               err = 0;
-                               goto exit;
-                       }
-
-                       /* Event on the registration socket */
-                       if (pollfd == sock) {
-                               if (revents & LPOLLIN) {
-                                       continue;
-                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
-                                       ERR("Health socket poll error");
-                                       goto error;
-                               } else {
-                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
-                                       goto error;
-                               }
-                       }
-               }
-
-               new_sock = lttcomm_accept_unix_sock(sock);
-               if (new_sock < 0) {
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, &get_info_return,
+                               sizeof(get_info_return));
+               if (ret < 0) {
+                       ret = -ret;
                        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);
+               ret = LTTNG_OK;
+               break;
+       }
+       case LTTNG_ROTATION_SET_SCHEDULE:
+       {
+               bool set_schedule;
+               enum lttng_rotation_schedule_type schedule_type;
+               uint64_t value;
 
-               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");
-                       }
-                       continue;
+               if (cmd_ctx->session->kernel_session && !check_rotate_compatible()) {
+                       DBG("Kernel tracer version does not support session rotations");
+                       ret = LTTNG_ERR_ROTATION_WRONG_VERSION;
+                       goto error;
                }
 
-               rcu_thread_online();
+               set_schedule = cmd_ctx->lsm->u.rotation_set_schedule.set == 1;
+               schedule_type = (enum lttng_rotation_schedule_type) cmd_ctx->lsm->u.rotation_set_schedule.type;
+               value = cmd_ctx->lsm->u.rotation_set_schedule.value;
 
-               memset(&reply, 0, sizeof(reply));
-               for (i = 0; i < NR_HEALTH_SESSIOND_TYPES; i++) {
-                       /*
-                        * health_check_state returns 0 if health is
-                        * bad.
-                        */
-                       if (!health_check_state(health_sessiond, i)) {
-                               reply.ret_code |= 1ULL << i;
-                       }
+               ret = cmd_rotation_set_schedule(cmd_ctx->session,
+                               set_schedule,
+                               schedule_type,
+                               value,
+                               notification_thread_handle);
+               if (ret != LTTNG_OK) {
+                       goto error;
                }
 
-               DBG2("Health check return value %" PRIx64, reply.ret_code);
-
-               ret = send_unix_sock(new_sock, (void *) &reply, sizeof(reply));
+               break;
+       }
+       case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
+       {
+               struct lttng_session_list_schedules_return schedules = {
+                       .periodic.set = !!cmd_ctx->session->rotate_timer_period,
+                       .periodic.value = cmd_ctx->session->rotate_timer_period,
+                       .size.set = !!cmd_ctx->session->rotate_size,
+                       .size.value = cmd_ctx->session->rotate_size,
+               };
+
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, &schedules,
+                               sizeof(schedules));
                if (ret < 0) {
-                       ERR("Failed to send health data back to client");
+                       ret = -ret;
+                       goto error;
                }
 
-               /* End of transmission */
-               ret = close(new_sock);
-               if (ret) {
-                       PERROR("close");
-               }
+               ret = LTTNG_OK;
+               break;
+       }
+       default:
+               ret = LTTNG_ERR_UND;
+               break;
        }
 
-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");
+       if (cmd_ctx->llm == NULL) {
+               DBG("Missing llm structure. Allocating one.");
+               if (setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0) < 0) {
+                       goto setup_error;
                }
        }
-
-       lttng_poll_clean(&events);
-       stop_threads();
-       rcu_unregister_thread();
-       return NULL;
+       /* Set return code */
+       cmd_ctx->llm->ret_code = ret;
+setup_error:
+       if (cmd_ctx->session) {
+               session_unlock(cmd_ctx->session);
+               session_put(cmd_ctx->session);
+       }
+       if (need_tracing_session) {
+               session_unlock_list();
+       }
+init_setup_error:
+       assert(!rcu_read_ongoing());
+       return ret;
 }
 
 /*
@@ -4473,13 +4233,41 @@ static void *thread_manage_clients(void *data)
                goto error;
        }
 
-       sessiond_notify_ready();
        ret = sem_post(&load_info->message_thread_ready);
        if (ret) {
                PERROR("sem_post message_thread_ready");
                goto error;
        }
 
+       /*
+        * Wait until all support threads are initialized before accepting
+        * commands.
+        */
+       while (uatomic_read(&lttng_sessiond_ready) != 0) {
+               /*
+                * If a support thread failed to launch, it may signal that
+                * we must exit and the sessiond would never be marked as
+                * "ready".
+                *
+                * The timeout is set to 1ms, which serves as a way to
+                * pace down this check.
+                */
+               ret = sessiond_wait_for_quit_pipe(1000);
+               if (ret > 0) {
+                       goto exit;
+               }
+       }
+       /*
+        * This barrier is paired with the one in sessiond_notify_ready() to
+        * ensure that loads accessing data initialized by the other threads,
+        * on which this thread was waiting, are not performed before this point.
+        *
+        * Note that this could be a 'read' memory barrier, but a full barrier
+        * is used in case the code changes. The performance implications of
+        * this choice are minimal since this is a slow path.
+        */
+       cmm_smp_mb();
+
        /* This testpoint is after we signal readiness to the parent. */
        if (testpoint(sessiond_thread_manage_clients)) {
                goto error;
@@ -4491,7 +4279,12 @@ static void *thread_manage_clients(void *data)
 
        health_code_update();
 
+       /* Set state as running. */
+       sessiond_set_client_thread_state(true);
+
        while (1) {
+               const struct cmd_completion_handler *cmd_completion_handler;
+
                DBG("Accepting client command ...");
 
                /* Inifinite blocking call, waiting for transmission */
@@ -4634,6 +4427,18 @@ static void *thread_manage_clients(void *data)
                        continue;
                }
 
+               cmd_completion_handler = cmd_pop_completion_handler();
+               if (cmd_completion_handler) {
+                       enum lttng_error_code completion_code;
+
+                       completion_code = cmd_completion_handler->run(
+                                       cmd_completion_handler->data);
+                       if (completion_code != LTTNG_OK) {
+                               clean_command_ctx(&cmd_ctx);
+                               continue;
+                       }
+               }
+
                health_code_update();
 
                DBG("Sending response (size: %d, retcode: %s (%d))",
@@ -4671,7 +4476,7 @@ error:
 
 error_listen:
 error_create_poll:
-       unlink(client_unix_sock_path);
+       unlink(config.client_unix_sock_path.value);
        if (client_sock >= 0) {
                ret = close(client_sock);
                if (ret) {
@@ -4711,6 +4516,9 @@ error_create_poll:
                errno = ret;
                PERROR("join_consumer ust64");
        }
+
+       /* Set state as non-running. */
+       sessiond_set_client_thread_state(false);
        return NULL;
 }
 
@@ -4738,7 +4546,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "-c, --client-sock");
                } else {
-                       snprintf(client_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.client_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.client_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "apps-sock") || opt == 'a') {
                if (!arg || *arg == '\0') {
@@ -4749,12 +4562,17 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "-a, --apps-sock");
                } else {
-                       snprintf(apps_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.apps_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.apps_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "daemonize") || opt == 'd') {
-               opt_daemon = 1;
+               config.daemonize = true;
        } else if (string_match(optname, "background") || opt == 'b') {
-               opt_background = 1;
+               config.background = true;
        } else if (string_match(optname, "group") || opt == 'g') {
                if (!arg || *arg == '\0') {
                        ret = -EINVAL;
@@ -4764,20 +4582,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "-g, --group");
                } else {
-                       /*
-                        * If the override option is set, the pointer points to a
-                        * *non* const thus freeing it even though the variable type is
-                        * set to const.
-                        */
-                       if (tracing_group_name_override) {
-                               free((void *) tracing_group_name);
-                       }
-                       tracing_group_name = strdup(arg);
-                       if (!tracing_group_name) {
-                               PERROR("strdup");
+                       config_string_set(&config.tracing_group_name,
+                                       strdup(arg));
+                       if (!config.tracing_group_name.value) {
                                ret = -ENOMEM;
+                               PERROR("strdup");
                        }
-                       tracing_group_name_override = 1;
                }
        } else if (string_match(optname, "help") || opt == 'h') {
                ret = utils_show_help(8, "lttng-sessiond", help_msg);
@@ -4790,7 +4600,7 @@ static int set_option(int opt, const char *arg, const char *optname)
                fprintf(stdout, "%s\n", VERSION);
                exit(EXIT_SUCCESS);
        } else if (string_match(optname, "sig-parent") || opt == 'S') {
-               opt_sig_parent = 1;
+               config.sig_parent = true;
        } else if (string_match(optname, "kconsumerd-err-sock")) {
                if (!arg || *arg == '\0') {
                        ret = -EINVAL;
@@ -4800,7 +4610,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--kconsumerd-err-sock");
                } else {
-                       snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.kconsumerd_err_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.kconsumerd_err_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "kconsumerd-cmd-sock")) {
                if (!arg || *arg == '\0') {
@@ -4811,7 +4626,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--kconsumerd-cmd-sock");
                } else {
-                       snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.kconsumerd_cmd_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.kconsumerd_cmd_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "ustconsumerd64-err-sock")) {
                if (!arg || *arg == '\0') {
@@ -4822,7 +4642,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--ustconsumerd64-err-sock");
                } else {
-                       snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.consumerd64_err_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.consumerd64_err_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "ustconsumerd64-cmd-sock")) {
                if (!arg || *arg == '\0') {
@@ -4833,7 +4658,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--ustconsumerd64-cmd-sock");
                } else {
-                       snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.consumerd64_cmd_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.consumerd64_cmd_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "ustconsumerd32-err-sock")) {
                if (!arg || *arg == '\0') {
@@ -4844,7 +4674,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--ustconsumerd32-err-sock");
                } else {
-                       snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX, "%s", arg);
+                       config_string_set(&config.consumerd32_err_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.consumerd32_err_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
        } else if (string_match(optname, "ustconsumerd32-cmd-sock")) {
                if (!arg || *arg == '\0') {
@@ -4855,29 +4690,34 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--ustconsumerd32-cmd-sock");
                } else {
-                       snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
-               }
+                       config_string_set(&config.consumerd32_cmd_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.consumerd32_cmd_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
+               }
        } else if (string_match(optname, "no-kernel")) {
-               opt_no_kernel = 1;
+               config.no_kernel = true;
        } else if (string_match(optname, "quiet") || opt == 'q') {
-               lttng_opt_quiet = 1;
+               config.quiet = true;
        } else if (string_match(optname, "verbose") || opt == 'v') {
                /* Verbose level can increase using multiple -v */
                if (arg) {
                        /* Value obtained from config file */
-                       lttng_opt_verbose = config_parse_value(arg);
+                       config.verbose = config_parse_value(arg);
                } else {
                        /* -v used on command line */
-                       lttng_opt_verbose++;
+                       config.verbose++;
                }
                /* Clamp value to [0, 3] */
-               lttng_opt_verbose = lttng_opt_verbose < 0 ? 0 :
-                       (lttng_opt_verbose <= 3 ? lttng_opt_verbose : 3);
+               config.verbose = config.verbose < 0 ? 0 :
+                       (config.verbose <= 3 ? config.verbose : 3);
        } else if (string_match(optname, "verbose-consumer")) {
                if (arg) {
-                       opt_verbose_consumer = config_parse_value(arg);
+                       config.verbose_consumer = config_parse_value(arg);
                } else {
-                       opt_verbose_consumer++;
+                       config.verbose_consumer++;
                }
        } else if (string_match(optname, "consumerd32-path")) {
                if (!arg || *arg == '\0') {
@@ -4888,15 +4728,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--consumerd32-path");
                } else {
-                       if (consumerd32_bin_override) {
-                               free((void *) consumerd32_bin);
-                       }
-                       consumerd32_bin = strdup(arg);
-                       if (!consumerd32_bin) {
+                       config_string_set(&config.consumerd32_bin_path,
+                                       strdup(arg));
+                       if (!config.consumerd32_bin_path.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
-                       consumerd32_bin_override = 1;
                }
        } else if (string_match(optname, "consumerd32-libdir")) {
                if (!arg || *arg == '\0') {
@@ -4907,15 +4744,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--consumerd32-libdir");
                } else {
-                       if (consumerd32_libdir_override) {
-                               free((void *) consumerd32_libdir);
-                       }
-                       consumerd32_libdir = strdup(arg);
-                       if (!consumerd32_libdir) {
+                       config_string_set(&config.consumerd32_lib_dir,
+                                       strdup(arg));
+                       if (!config.consumerd32_lib_dir.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
-                       consumerd32_libdir_override = 1;
                }
        } else if (string_match(optname, "consumerd64-path")) {
                if (!arg || *arg == '\0') {
@@ -4926,15 +4760,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--consumerd64-path");
                } else {
-                       if (consumerd64_bin_override) {
-                               free((void *) consumerd64_bin);
-                       }
-                       consumerd64_bin = strdup(arg);
-                       if (!consumerd64_bin) {
+                       config_string_set(&config.consumerd64_bin_path,
+                                       strdup(arg));
+                       if (!config.consumerd64_bin_path.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
-                       consumerd64_bin_override = 1;
                }
        } else if (string_match(optname, "consumerd64-libdir")) {
                if (!arg || *arg == '\0') {
@@ -4945,15 +4776,12 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--consumerd64-libdir");
                } else {
-                       if (consumerd64_libdir_override) {
-                               free((void *) consumerd64_libdir);
-                       }
-                       consumerd64_libdir = strdup(arg);
-                       if (!consumerd64_libdir) {
+                       config_string_set(&config.consumerd64_lib_dir,
+                                       strdup(arg));
+                       if (!config.consumerd64_lib_dir.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
-                       consumerd64_libdir_override = 1;
                }
        } else if (string_match(optname, "pidfile") || opt == 'p') {
                if (!arg || *arg == '\0') {
@@ -4964,9 +4792,8 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "-p, --pidfile");
                } else {
-                       free(opt_pidfile);
-                       opt_pidfile = strdup(arg);
-                       if (!opt_pidfile) {
+                       config_string_set(&config.pid_file_path, strdup(arg));
+                       if (!config.pid_file_path.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
@@ -4992,8 +4819,8 @@ static int set_option(int opt, const char *arg, const char *optname)
                                ERR("Port overflow in --agent-tcp-port parameter: %s", arg);
                                return -1;
                        }
-                       agent_tcp_port = (uint32_t) v;
-                       DBG3("Agent TCP port set to non default: %u", agent_tcp_port);
+                       config.agent_tcp_port.begin = config.agent_tcp_port.end = (int) v;
+                       DBG3("Agent TCP port set to non default: %i", (int) v);
                }
        } else if (string_match(optname, "load") || opt == 'l') {
                if (!arg || *arg == '\0') {
@@ -5004,9 +4831,8 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "-l, --load");
                } else {
-                       free(opt_load_session_path);
-                       opt_load_session_path = strdup(arg);
-                       if (!opt_load_session_path) {
+                       config_string_set(&config.load_session_path, strdup(arg));
+                       if (!config.load_session_path.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
@@ -5020,9 +4846,8 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--kmod-probes");
                } else {
-                       free(kmod_probes_list);
-                       kmod_probes_list = strdup(arg);
-                       if (!kmod_probes_list) {
+                       config_string_set(&config.kmod_probes_list, strdup(arg));
+                       if (!config.kmod_probes_list.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
@@ -5036,9 +4861,9 @@ static int set_option(int opt, const char *arg, const char *optname)
                        WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
                                "--extra-kmod-probes");
                } else {
-                       free(kmod_extra_probes_list);
-                       kmod_extra_probes_list = strdup(arg);
-                       if (!kmod_extra_probes_list) {
+                       config_string_set(&config.kmod_extra_probes_list,
+                                       strdup(arg));
+                       if (!config.kmod_extra_probes_list.value) {
                                PERROR("strdup");
                                ret = -ENOMEM;
                        }
@@ -5222,9 +5047,9 @@ static int init_daemon_socket(void)
        old_umask = umask(0);
 
        /* Create client tool unix socket */
-       client_sock = lttcomm_create_unix_sock(client_unix_sock_path);
+       client_sock = lttcomm_create_unix_sock(config.client_unix_sock_path.value);
        if (client_sock < 0) {
-               ERR("Create unix sock failed: %s", client_unix_sock_path);
+               ERR("Create unix sock failed: %s", config.client_unix_sock_path.value);
                ret = -1;
                goto end;
        }
@@ -5238,17 +5063,17 @@ static int init_daemon_socket(void)
        }
 
        /* File permission MUST be 660 */
-       ret = chmod(client_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+       ret = chmod(config.client_unix_sock_path.value, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
        if (ret < 0) {
-               ERR("Set file permissions failed: %s", client_unix_sock_path);
+               ERR("Set file permissions failed: %s", config.client_unix_sock_path.value);
                PERROR("chmod");
                goto end;
        }
 
        /* Create the application unix socket */
-       apps_sock = lttcomm_create_unix_sock(apps_unix_sock_path);
+       apps_sock = lttcomm_create_unix_sock(config.apps_unix_sock_path.value);
        if (apps_sock < 0) {
-               ERR("Create unix sock failed: %s", apps_unix_sock_path);
+               ERR("Create unix sock failed: %s", config.apps_unix_sock_path.value);
                ret = -1;
                goto end;
        }
@@ -5262,10 +5087,10 @@ static int init_daemon_socket(void)
        }
 
        /* File permission MUST be 666 */
-       ret = chmod(apps_unix_sock_path,
+       ret = chmod(config.apps_unix_sock_path.value,
                        S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
        if (ret < 0) {
-               ERR("Set file permissions failed: %s", apps_unix_sock_path);
+               ERR("Set file permissions failed: %s", config.apps_unix_sock_path.value);
                PERROR("chmod");
                goto end;
        }
@@ -5278,18 +5103,57 @@ end:
        return ret;
 }
 
+/*
+ * Create lockfile using the rundir and return its fd.
+ */
+static int create_lockfile(void)
+{
+        return utils_create_lock_file(config.lock_file_path.value);
+}
+
 /*
  * Check if the global socket is available, and if a daemon is answering at the
  * other side. If yes, error is returned.
+ *
+ * Also attempts to create and hold the lock file.
  */
 static int check_existing_daemon(void)
 {
+       int ret = 0;
+
        /* Is there anybody out there ? */
        if (lttng_session_daemon_alive()) {
-               return -EEXIST;
+               ret = -EEXIST;
+               goto end;
        }
 
-       return 0;
+       lockfile_fd = create_lockfile();
+       if (lockfile_fd < 0) {
+               ret = -EEXIST;
+               goto end;
+       }
+end:
+       return ret;
+}
+
+static void sessiond_cleanup_lock_file(void)
+{
+       int ret;
+
+       /*
+        * Cleanup lock file by deleting it and finaly closing it which will
+        * release the file system lock.
+        */
+       if (lockfile_fd >= 0) {
+               ret = remove(config.lock_file_path.value);
+               if (ret < 0) {
+                       PERROR("remove lock file");
+               }
+               ret = close(lockfile_fd);
+               if (ret < 0) {
+                       PERROR("close lock file");
+               }
+       }
 }
 
 /*
@@ -5303,7 +5167,7 @@ static int set_permissions(char *rundir)
        int ret;
        gid_t gid;
 
-       gid = utils_get_group_id(tracing_group_name);
+       gid = utils_get_group_id(config.tracing_group_name.value);
 
        /* Set lttng run dir */
        ret = chown(rundir, 0, gid);
@@ -5324,9 +5188,9 @@ static int set_permissions(char *rundir)
        }
 
        /* lttng client socket path */
-       ret = chown(client_unix_sock_path, 0, gid);
+       ret = chown(config.client_unix_sock_path.value, 0, gid);
        if (ret < 0) {
-               ERR("Unable to set group on %s", client_unix_sock_path);
+               ERR("Unable to set group on %s", config.client_unix_sock_path.value);
                PERROR("chown");
        }
 
@@ -5359,16 +5223,16 @@ static int set_permissions(char *rundir)
 /*
  * Create the lttng run directory needed for all global sockets and pipe.
  */
-static int create_lttng_rundir(const char *rundir)
+static int create_lttng_rundir(void)
 {
        int ret;
 
-       DBG3("Creating LTTng run directory: %s", rundir);
+       DBG3("Creating LTTng run directory: %s", config.rundir.value);
 
-       ret = mkdir(rundir, S_IRWXU);
+       ret = mkdir(config.rundir.value, S_IRWXU);
        if (ret < 0) {
                if (errno != EEXIST) {
-                       ERR("Unable to create %s", rundir);
+                       ERR("Unable to create %s", config.rundir.value);
                        goto error;
                } else {
                        ret = 0;
@@ -5380,30 +5244,30 @@ error:
 }
 
 /*
- * Setup sockets and directory needed by the kconsumerd communication with the
+ * Setup sockets and directory needed by the consumerds' communication with the
  * session daemon.
  */
-static int set_consumer_sockets(struct consumer_data *consumer_data,
-               const char *rundir)
+static int set_consumer_sockets(struct consumer_data *consumer_data)
 {
        int ret;
-       char path[PATH_MAX];
+       char *path = NULL;
 
        switch (consumer_data->type) {
        case LTTNG_CONSUMER_KERNEL:
-               snprintf(path, PATH_MAX, DEFAULT_KCONSUMERD_PATH, rundir);
+               path = config.kconsumerd_path.value;
                break;
        case LTTNG_CONSUMER64_UST:
-               snprintf(path, PATH_MAX, DEFAULT_USTCONSUMERD64_PATH, rundir);
+               path = config.consumerd64_path.value;
                break;
        case LTTNG_CONSUMER32_UST:
-               snprintf(path, PATH_MAX, DEFAULT_USTCONSUMERD32_PATH, rundir);
+               path = config.consumerd32_path.value;
                break;
        default:
                ERR("Consumer type unknown");
                ret = -EINVAL;
                goto error;
        }
+       assert(path);
 
        DBG2("Creating consumer directory: %s", path);
 
@@ -5414,7 +5278,7 @@ static int set_consumer_sockets(struct consumer_data *consumer_data,
                goto error;
        }
        if (is_root) {
-               ret = chown(path, 0, utils_get_group_id(tracing_group_name));
+               ret = chown(path, 0, utils_get_group_id(config.tracing_group_name.value));
                if (ret < 0) {
                        ERR("Unable to set group on %s", path);
                        PERROR("chown");
@@ -5422,7 +5286,7 @@ static int set_consumer_sockets(struct consumer_data *consumer_data,
                }
        }
 
-       /* Create the kconsumerd error unix socket */
+       /* Create the consumerd error unix socket */
        consumer_data->err_sock =
                lttcomm_create_unix_sock(consumer_data->err_unix_sock_path);
        if (consumer_data->err_sock < 0) {
@@ -5543,81 +5407,82 @@ static void set_ulimit(void)
        }
 }
 
-/*
- * Write pidfile using the rundir and opt_pidfile.
- */
 static int write_pidfile(void)
 {
-       int ret;
-       char pidfile_path[PATH_MAX];
-
-       assert(rundir);
-
-       if (opt_pidfile) {
-               if (lttng_strncpy(pidfile_path, opt_pidfile, sizeof(pidfile_path))) {
-                       ret = -1;
-                       goto error;
-               }
-       } else {
-               /* Build pidfile path from rundir and opt_pidfile. */
-               ret = snprintf(pidfile_path, sizeof(pidfile_path), "%s/"
-                               DEFAULT_LTTNG_SESSIOND_PIDFILE, rundir);
-               if (ret < 0) {
-                       PERROR("snprintf pidfile path");
-                       goto error;
-               }
-       }
-
-       /*
-        * Create pid file in rundir.
-        */
-       ret = utils_create_pid_file(getpid(), pidfile_path);
-error:
-       return ret;
+        return utils_create_pid_file(getpid(), config.pid_file_path.value);
 }
 
-/*
- * Create lockfile using the rundir and return its fd.
- */
-static int create_lockfile(void)
+static int set_clock_plugin_env(void)
 {
-       int ret;
-       char lockfile_path[PATH_MAX];
+       int ret = 0;
+       char *env_value = NULL;
 
-       ret = generate_lock_file_path(lockfile_path, sizeof(lockfile_path));
+       if (!config.lttng_ust_clock_plugin.value) {
+               goto end;
+       }
+
+        ret = asprintf(&env_value, "LTTNG_UST_CLOCK_PLUGIN=%s",
+                       config.lttng_ust_clock_plugin.value);
        if (ret < 0) {
-               goto error;
+               PERROR("asprintf");
+               goto end;
        }
 
-       ret = utils_create_lock_file(lockfile_path);
-error:
+       ret = putenv(env_value);
+       if (ret) {
+               free(env_value);
+               PERROR("putenv of LTTNG_UST_CLOCK_PLUGIN");
+               goto end;
+       }
+
+       DBG("Updated LTTNG_UST_CLOCK_PLUGIN environment variable to \"%s\"",
+                       config.lttng_ust_clock_plugin.value);
+end:
        return ret;
 }
 
-/*
- * Write agent TCP port using the rundir.
- */
-static int write_agent_port(void)
+static void destroy_all_sessions_and_wait(void)
 {
-       int ret;
-       char path[PATH_MAX];
+       struct ltt_session *session, *tmp;
+       struct ltt_session_list *session_list;
 
-       assert(rundir);
+       session_list = session_get_list();
+       DBG("Initiating destruction of all sessions");
 
-       ret = snprintf(path, sizeof(path), "%s/"
-                       DEFAULT_LTTNG_SESSIOND_AGENTPORT_FILE, rundir);
-       if (ret < 0) {
-               PERROR("snprintf agent port path");
-               goto error;
+       if (!session_list) {
+               return;
        }
 
        /*
-        * Create TCP agent port file in rundir.
+        * Ensure that the client thread is no longer accepting new commands,
+        * which could cause new sessions to be created.
         */
-       ret = utils_create_pid_file(agent_tcp_port, path);
+       sessiond_wait_client_thread_stopped();
 
-error:
-       return ret;
+       session_lock_list();
+       /* Initiate the destruction of all sessions. */
+       cds_list_for_each_entry_safe(session, tmp,
+                       &session_list->head, list) {
+               if (!session_get(session)) {
+                       continue;
+               }
+
+               session_lock(session);
+               if (session->destroyed) {
+                       goto unlock_session;
+               }
+               (void) cmd_destroy_session(session,
+                               notification_thread_handle);
+       unlock_session:
+               session_unlock(session);
+               session_put(session);
+       }
+       session_unlock_list();
+
+       /* Wait for the destruction of all sessions to complete. */
+       DBG("Waiting for the destruction of all sessions to complete");
+       session_list_wait_empty();
+       DBG("Destruction of all sessions completed");
 }
 
 /*
@@ -5627,11 +5492,16 @@ int main(int argc, char **argv)
 {
        int ret = 0, retval = 0;
        void *status;
-       const char *home_path, *env_app_timeout;
+       const char *env_app_timeout;
        struct lttng_pipe *ust32_channel_monitor_pipe = NULL,
                        *ust64_channel_monitor_pipe = NULL,
                        *kernel_channel_monitor_pipe = NULL;
-       bool notification_thread_running = false;
+       bool rotation_thread_launched = false;
+       bool timer_thread_launched = false;
+       struct lttng_thread *ht_cleanup_thread = NULL;
+       struct timer_thread_parameters timer_thread_ctx;
+       /* Queue of rotation jobs populated by the sessiond-timer. */
+       struct rotation_thread_timer_queue *rotation_timer_queue = NULL;
 
        init_kernel_workarounds();
 
@@ -5642,7 +5512,10 @@ int main(int argc, char **argv)
                goto exit_set_signal_handler;
        }
 
-       setup_consumerd_path();
+       if (timer_signal_init()) {
+               retval = -1;
+               goto exit_set_signal_handler;
+       }
 
        page_size = sysconf(_SC_PAGESIZE);
        if (page_size < 0) {
@@ -5651,6 +5524,18 @@ int main(int argc, char **argv)
                WARN("Fallback page size to %ld", page_size);
        }
 
+       ret = sessiond_config_init(&config);
+       if (ret) {
+               retval = -1;
+               goto exit_set_signal_handler;
+       }
+
+       /*
+        * Init config from environment variables.
+        * Command line option override env configuration per-doc. Do env first.
+        */
+       sessiond_config_apply_env_config(&config);
+
        /*
         * Parse arguments and load the daemon configuration file.
         *
@@ -5665,12 +5550,54 @@ int main(int argc, char **argv)
                goto exit_options;
        }
 
+       /*
+        * Resolve all paths received as arguments, configuration option, or
+        * through environment variable as absolute paths. This is necessary
+        * since daemonizing causes the sessiond's current working directory
+        * to '/'.
+        */
+       ret = sessiond_config_resolve_paths(&config);
+       if (ret) {
+               goto exit_options;
+       }
+
+       /* Apply config. */
+       lttng_opt_verbose = config.verbose;
+       lttng_opt_quiet = config.quiet;
+       kconsumer_data.err_unix_sock_path =
+                       config.kconsumerd_err_unix_sock_path.value;
+       kconsumer_data.cmd_unix_sock_path =
+                       config.kconsumerd_cmd_unix_sock_path.value;
+       ustconsumer32_data.err_unix_sock_path =
+                       config.consumerd32_err_unix_sock_path.value;
+       ustconsumer32_data.cmd_unix_sock_path =
+                       config.consumerd32_cmd_unix_sock_path.value;
+       ustconsumer64_data.err_unix_sock_path =
+                       config.consumerd64_err_unix_sock_path.value;
+       ustconsumer64_data.cmd_unix_sock_path =
+                       config.consumerd64_cmd_unix_sock_path.value;
+       set_clock_plugin_env();
+
+       sessiond_config_log(&config);
+
+       if (create_lttng_rundir()) {
+               retval = -1;
+               goto exit_options;
+       }
+
+       /* Abort launch if a session daemon is already running. */
+       if (check_existing_daemon()) {
+               ERR("A session daemon is already running.");
+               retval = -1;
+               goto exit_options;
+       }
+
        /* Daemonize */
-       if (opt_daemon || opt_background) {
+       if (config.daemonize || config.background) {
                int i;
 
                ret = lttng_daemonize(&child_ppid, &recv_child_signal,
-                       !opt_background);
+                       !config.background);
                if (ret < 0) {
                        retval = -1;
                        goto exit_options;
@@ -5679,9 +5606,12 @@ int main(int argc, char **argv)
                /*
                 * We are in the child. Make sure all other file descriptors are
                 * closed, in case we are called with more opened file
-                * descriptors than the standard ones.
+                * descriptors than the standard ones and the lock file.
                 */
                for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
+                       if (i == lockfile_fd) {
+                               continue;
+                       }
                        (void) close(i);
                }
        }
@@ -5707,89 +5637,23 @@ int main(int argc, char **argv)
        }
 
        /* Create thread to clean up RCU hash tables */
-       if (init_ht_cleanup_thread(&ht_cleanup_thread)) {
+       ht_cleanup_thread = launch_ht_cleanup_thread();
+       if (!ht_cleanup_thread) {
                retval = -1;
                goto exit_ht_cleanup;
        }
 
        /* Create thread quit pipe */
-       if (init_thread_quit_pipe()) {
+       if (sessiond_init_thread_quit_pipe()) {
                retval = -1;
                goto exit_init_data;
        }
 
        /* Check if daemon is UID = 0 */
        is_root = !getuid();
-
        if (is_root) {
-               rundir = strdup(DEFAULT_LTTNG_RUNDIR);
-               if (!rundir) {
-                       retval = -1;
-                       goto exit_init_data;
-               }
-
                /* Create global run dir with root access */
-               if (create_lttng_rundir(rundir)) {
-                       retval = -1;
-                       goto exit_init_data;
-               }
-
-               if (strlen(apps_unix_sock_path) == 0) {
-                       ret = snprintf(apps_unix_sock_path, PATH_MAX,
-                                       DEFAULT_GLOBAL_APPS_UNIX_SOCK);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-
-               if (strlen(client_unix_sock_path) == 0) {
-                       ret = snprintf(client_unix_sock_path, PATH_MAX,
-                                       DEFAULT_GLOBAL_CLIENT_UNIX_SOCK);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
 
-               /* Set global SHM for ust */
-               if (strlen(wait_shm_path) == 0) {
-                       ret = snprintf(wait_shm_path, PATH_MAX,
-                                       DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-
-               if (strlen(health_unix_sock_path) == 0) {
-                       ret = snprintf(health_unix_sock_path,
-                                       sizeof(health_unix_sock_path),
-                                       DEFAULT_GLOBAL_HEALTH_UNIX_SOCK);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-
-               /* Setup kernel consumerd path */
-               ret = snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX,
-                               DEFAULT_KCONSUMERD_ERR_SOCK_PATH, rundir);
-               if (ret < 0) {
-                       retval = -1;
-                       goto exit_init_data;
-               }
-               ret = snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX,
-                               DEFAULT_KCONSUMERD_CMD_SOCK_PATH, rundir);
-               if (ret < 0) {
-                       retval = -1;
-                       goto exit_init_data;
-               }
-
-               DBG2("Kernel consumer err path: %s",
-                               kconsumer_data.err_unix_sock_path);
-               DBG2("Kernel consumer cmd path: %s",
-                               kconsumer_data.cmd_unix_sock_path);
                kernel_channel_monitor_pipe = lttng_pipe_open(0);
                if (!kernel_channel_monitor_pipe) {
                        ERR("Failed to create kernel consumer channel monitor pipe");
@@ -5803,110 +5667,12 @@ int main(int argc, char **argv)
                        retval = -1;
                        goto exit_init_data;
                }
-       } 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.");
-                       retval = -1;
-                       goto exit_init_data;
-               }
-
-               /*
-                * Create rundir from home path. This will create something like
-                * $HOME/.lttng
-                */
-               ret = asprintf(&rundir, DEFAULT_LTTNG_HOME_RUNDIR, home_path);
-               if (ret < 0) {
-                       retval = -1;
-                       goto exit_init_data;
-               }
-
-               if (create_lttng_rundir(rundir)) {
-                       retval = -1;
-                       goto exit_init_data;
-               }
-
-               if (strlen(apps_unix_sock_path) == 0) {
-                       ret = snprintf(apps_unix_sock_path, PATH_MAX,
-                                       DEFAULT_HOME_APPS_UNIX_SOCK,
-                                       home_path);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-
-               /* Set the cli tool unix socket path */
-               if (strlen(client_unix_sock_path) == 0) {
-                       ret = snprintf(client_unix_sock_path, PATH_MAX,
-                                       DEFAULT_HOME_CLIENT_UNIX_SOCK,
-                                       home_path);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-
-               /* Set global SHM for ust */
-               if (strlen(wait_shm_path) == 0) {
-                       ret = snprintf(wait_shm_path, PATH_MAX,
-                                       DEFAULT_HOME_APPS_WAIT_SHM_PATH,
-                                       getuid());
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-
-               /* Set health check Unix path */
-               if (strlen(health_unix_sock_path) == 0) {
-                       ret = snprintf(health_unix_sock_path,
-                                       sizeof(health_unix_sock_path),
-                                       DEFAULT_HOME_HEALTH_UNIX_SOCK,
-                                       home_path);
-                       if (ret < 0) {
-                               retval = -1;
-                               goto exit_init_data;
-                       }
-               }
-       }
-
-       lockfile_fd = create_lockfile();
-       if (lockfile_fd < 0) {
-               retval = -1;
-               goto exit_init_data;
        }
 
        /* Set consumer initial state */
        kernel_consumerd_state = CONSUMER_STOPPED;
        ust_consumerd_state = CONSUMER_STOPPED;
 
-       DBG("Client socket path %s", client_unix_sock_path);
-       DBG("Application socket path %s", apps_unix_sock_path);
-       DBG("Application wait path %s", wait_shm_path);
-       DBG("LTTng run directory path: %s", rundir);
-
-       /* 32 bits consumerd path setup */
-       ret = snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH, rundir);
-       if (ret < 0) {
-               PERROR("snprintf 32-bit consumer error socket path");
-               retval = -1;
-               goto exit_init_data;
-       }
-       ret = snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD32_CMD_SOCK_PATH, rundir);
-       if (ret < 0) {
-               PERROR("snprintf 32-bit consumer command socket path");
-               retval = -1;
-               goto exit_init_data;
-       }
-
-       DBG2("UST consumer 32 bits err path: %s",
-                       ustconsumer32_data.err_unix_sock_path);
-       DBG2("UST consumer 32 bits cmd path: %s",
-                       ustconsumer32_data.cmd_unix_sock_path);
        ust32_channel_monitor_pipe = lttng_pipe_open(0);
        if (!ust32_channel_monitor_pipe) {
                ERR("Failed to create 32-bit user space consumer channel monitor pipe");
@@ -5920,26 +5686,18 @@ int main(int argc, char **argv)
                goto exit_init_data;
        }
 
-       /* 64 bits consumerd path setup */
-       ret = snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH, rundir);
-       if (ret < 0) {
-               PERROR("snprintf 64-bit consumer error socket path");
-               retval = -1;
-               goto exit_init_data;
-       }
-       ret = snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD64_CMD_SOCK_PATH, rundir);
-       if (ret < 0) {
-               PERROR("snprintf 64-bit consumer command socket path");
+       /*
+        * The rotation_thread_timer_queue structure is shared between the
+        * sessiond timer thread and the rotation thread. The main thread keeps
+        * its ownership and destroys it when both threads have been joined.
+        */
+       rotation_timer_queue = rotation_thread_timer_queue_create();
+       if (!rotation_timer_queue) {
                retval = -1;
                goto exit_init_data;
        }
+       timer_thread_ctx.rotation_thread_job_queue = rotation_timer_queue;
 
-       DBG2("UST consumer 64 bits err path: %s",
-                       ustconsumer64_data.err_unix_sock_path);
-       DBG2("UST consumer 64 bits cmd path: %s",
-                       ustconsumer64_data.cmd_unix_sock_path);
        ust64_channel_monitor_pipe = lttng_pipe_open(0);
        if (!ust64_channel_monitor_pipe) {
                ERR("Failed to create 64-bit user space consumer channel monitor pipe");
@@ -5953,19 +5711,6 @@ int main(int argc, char **argv)
                goto exit_init_data;
        }
 
-       /*
-        * See if daemon already exist.
-        */
-       if (check_existing_daemon()) {
-               ERR("Already running daemon.\n");
-               /*
-                * We do not goto exit because we must not cleanup()
-                * because a daemon is already running.
-                */
-               retval = -1;
-               goto exit_init_data;
-       }
-
        /*
         * Init UST app hash table. Alloc hash table before this point since
         * cleanup() can get called after that point.
@@ -5993,13 +5738,13 @@ int main(int argc, char **argv)
         * kernel tracer.
         */
        if (is_root) {
-               if (set_consumer_sockets(&kconsumer_data, rundir)) {
+               if (set_consumer_sockets(&kconsumer_data)) {
                        retval = -1;
                        goto exit_init_data;
                }
 
                /* Setup kernel tracer */
-               if (!opt_no_kernel) {
+               if (!config.no_kernel) {
                        init_kernel_tracer();
                        if (kernel_tracer_fd >= 0) {
                                ret = syscall_init_table();
@@ -6017,12 +5762,12 @@ int main(int argc, char **argv)
        /* init lttng_fd tracking must be done after set_ulimit. */
        lttng_fd_init();
 
-       if (set_consumer_sockets(&ustconsumer64_data, rundir)) {
+       if (set_consumer_sockets(&ustconsumer64_data)) {
                retval = -1;
                goto exit_init_data;
        }
 
-       if (set_consumer_sockets(&ustconsumer32_data, rundir)) {
+       if (set_consumer_sockets(&ustconsumer32_data)) {
                retval = -1;
                goto exit_init_data;
        }
@@ -6034,18 +5779,18 @@ int main(int argc, char **argv)
        }
 
        /* Set credentials to socket */
-       if (is_root && set_permissions(rundir)) {
+       if (is_root && set_permissions(config.rundir.value)) {
                retval = -1;
                goto exit_init_data;
        }
 
        /* Get parent pid if -S, --sig-parent is specified. */
-       if (opt_sig_parent) {
+       if (config.sig_parent) {
                ppid = getppid();
        }
 
        /* Setup the kernel pipe for waking up the kernel thread */
-       if (is_root && !opt_no_kernel) {
+       if (is_root && !config.no_kernel) {
                if (utils_create_pipe_cloexec(kernel_poll_pipe)) {
                        retval = -1;
                        goto exit_init_data;
@@ -6071,20 +5816,14 @@ int main(int argc, char **argv)
        /* Init UST command queue. */
        cds_wfcq_init(&ust_cmd_queue.head, &ust_cmd_queue.tail);
 
-       /*
-        * Get session list pointer. This pointer MUST NOT be free'd. This list
-        * is statically declared in session.c
-        */
-       session_list_ptr = session_get_list();
-
        cmd_init();
 
        /* Check for the application socket timeout env variable. */
        env_app_timeout = getenv(DEFAULT_APP_SOCKET_TIMEOUT_ENV);
        if (env_app_timeout) {
-               app_socket_timeout = atoi(env_app_timeout);
+               config.app_socket_timeout = atoi(env_app_timeout);
        } else {
-               app_socket_timeout = DEFAULT_APP_SOCKET_RW_TIMEOUT;
+               config.app_socket_timeout = DEFAULT_APP_SOCKET_RW_TIMEOUT;
        }
 
        ret = write_pidfile();
@@ -6093,12 +5832,6 @@ int main(int argc, char **argv)
                retval = -1;
                goto exit_init_data;
        }
-       ret = write_agent_port();
-       if (ret) {
-               ERR("Error in write_agent_port");
-               retval = -1;
-               goto exit_init_data;
-       }
 
        /* Initialize communication library */
        lttcomm_init();
@@ -6109,14 +5842,10 @@ int main(int argc, char **argv)
                retval = -1;
                goto exit_init_data;
        }
-       load_info->path = opt_load_session_path;
+       load_info->path = config.load_session_path.value;
 
        /* Create health-check thread. */
-       ret = pthread_create(&health_thread, default_pthread_attr(),
-                       thread_manage_health, (void *) NULL);
-       if (ret) {
-               errno = ret;
-               PERROR("pthread_create health");
+       if (!launch_health_management_thread()) {
                retval = -1;
                goto exit_health;
        }
@@ -6129,21 +5858,50 @@ int main(int argc, char **argv)
        if (!notification_thread_handle) {
                retval = -1;
                ERR("Failed to create notification thread shared data");
-               stop_threads();
                goto exit_notification;
        }
 
        /* Create notification thread. */
-       ret = pthread_create(&notification_thread, default_pthread_attr(),
-                       thread_notification, notification_thread_handle);
+       if (!launch_notification_thread(notification_thread_handle)) {
+               retval = -1;
+               goto exit_notification;
+
+       }
+
+       /* Create timer thread. */
+       ret = pthread_create(&timer_thread, default_pthread_attr(),
+                       timer_thread_func, &timer_thread_ctx);
        if (ret) {
                errno = ret;
-               PERROR("pthread_create notification");
+               PERROR("pthread_create timer");
                retval = -1;
                stop_threads();
                goto exit_notification;
        }
-       notification_thread_running = true;
+       timer_thread_launched = true;
+
+       /* rotation_thread_data acquires the pipes' read side. */
+       rotation_thread_handle = rotation_thread_handle_create(
+                       rotation_timer_queue,
+                       notification_thread_handle);
+       if (!rotation_thread_handle) {
+               retval = -1;
+               ERR("Failed to create rotation thread shared data");
+               stop_threads();
+               goto exit_rotation;
+       }
+
+       /* Create rotation thread. */
+       ret = pthread_create(&rotation_thread, default_pthread_attr(),
+                       thread_rotation, rotation_thread_handle);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create rotation");
+               retval = -1;
+               stop_threads();
+               goto exit_rotation;
+       }
+       rotation_thread_launched = true;
 
        /* Create thread to manage the client socket */
        ret = pthread_create(&client_thread, default_pthread_attr(),
@@ -6212,7 +5970,7 @@ int main(int argc, char **argv)
        }
 
        /* Don't start this thread if kernel tracing is not requested nor root */
-       if (is_root && !opt_no_kernel) {
+       if (is_root && !config.no_kernel) {
                /* Create kernel thread to manage kernel event */
                ret = pthread_create(&kernel_thread, default_pthread_attr(),
                                thread_manage_kernel, (void *) NULL);
@@ -6247,9 +6005,13 @@ int main(int argc, char **argv)
                PERROR("pthread_join load_session_thread");
                retval = -1;
        }
+
+       /* Initiate teardown once activity occurs on the quit pipe. */
+       sessiond_wait_for_quit_pipe(-1U);
+       destroy_all_sessions_and_wait();
 exit_load_session:
 
-       if (is_root && !opt_no_kernel) {
+       if (is_root && !config.no_kernel) {
                ret = pthread_join(kernel_thread, &status);
                if (ret) {
                        errno = ret;
@@ -6311,14 +6073,9 @@ exit_dispatch:
        }
 
 exit_client:
+exit_rotation:
 exit_notification:
-       ret = pthread_join(health_thread, &status);
-       if (ret) {
-               errno = ret;
-               PERROR("pthread_join health thread");
-               retval = -1;
-       }
-
+       lttng_thread_list_shutdown_orphans();
 exit_health:
 exit_init_data:
        /*
@@ -6341,31 +6098,49 @@ exit_init_data:
         */
        rcu_barrier();
 
-       /*
-        * The teardown of the notification system is performed after the
-        * session daemon's teardown in order to allow it to be notified
-        * of the active session and channels at the moment of the teardown.
-        */
-       if (notification_thread_handle) {
-               if (notification_thread_running) {
-                       notification_thread_command_quit(
-                                       notification_thread_handle);
-                       ret = pthread_join(notification_thread, &status);
+       if (rotation_thread_handle) {
+               if (rotation_thread_launched) {
+                       ret = pthread_join(rotation_thread, &status);
                        if (ret) {
                                errno = ret;
-                               PERROR("pthread_join notification thread");
+                               PERROR("pthread_join rotation thread");
                                retval = -1;
                        }
                }
-               notification_thread_handle_destroy(notification_thread_handle);
+               rotation_thread_handle_destroy(rotation_thread_handle);
+       }
+
+       if (timer_thread_launched) {
+               timer_exit();
+               ret = pthread_join(timer_thread, &status);
+               if (ret) {
+                       errno = ret;
+                       PERROR("pthread_join timer thread");
+                       retval = -1;
+               }
        }
 
+       if (ht_cleanup_thread) {
+               lttng_thread_shutdown(ht_cleanup_thread);
+               lttng_thread_put(ht_cleanup_thread);
+       }
+
+       /*
+        * After the rotation and timer thread have quit, we can safely destroy
+        * the rotation_timer_queue.
+        */
+       rotation_thread_timer_queue_destroy(rotation_timer_queue);
+
        rcu_thread_offline();
        rcu_unregister_thread();
 
-       ret = fini_ht_cleanup_thread(&ht_cleanup_thread);
-       if (ret) {
-               retval = -1;
+       /*
+        * The teardown of the notification system is performed after the
+        * session daemon's teardown in order to allow it to be notified
+        * of the active session and channels at the moment of the teardown.
+        */
+       if (notification_thread_handle) {
+               notification_thread_handle_destroy(notification_thread_handle);
        }
        lttng_pipe_destroy(ust32_channel_monitor_pipe);
        lttng_pipe_destroy(ust64_channel_monitor_pipe);
@@ -6377,6 +6152,7 @@ exit_health_sessiond_cleanup:
 exit_create_run_as_worker_cleanup:
 
 exit_options:
+       sessiond_cleanup_lock_file();
        sessiond_cleanup_options();
 
 exit_set_signal_handler:
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