centralize sessiond config option handling
[lttng-tools.git] / src / bin / lttng-sessiond / main.c
index a970012c7fde9fc90464adfd2520add2e6a3a903..10802aa7b2cc66d87d0946ee53623b05b47a1c0f 100644 (file)
@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
 #define _LGPL_SOURCE
 #include <getopt.h>
 #include <grp.h>
 #include <sys/wait.h>
 #include <urcu/uatomic.h>
 #include <unistd.h>
-#include <config.h>
+#include <ctype.h>
 
 #include <common/common.h>
 #include <common/compat/socket.h>
+#include <common/compat/getenv.h>
 #include <common/defaults.h>
 #include <common/kernel-consumer/kernel-consumer.h>
 #include <common/futex.h>
 #include <common/relayd/relayd.h>
 #include <common/utils.h>
 #include <common/daemonize.h>
-#include <common/config/config.h>
+#include <common/config/session-config.h>
 
 #include "lttng-sessiond.h"
 #include "buffer-registry.h"
 #include "agent-thread.h"
 #include "save.h"
 #include "load-session-thread.h"
+#include "notification-thread.h"
+#include "notification-thread-commands.h"
 #include "syscall.h"
+#include "agent.h"
+#include "ht-cleanup.h"
+#include "sessiond-config.h"
 
-#define CONSUMERD_FILE "lttng-consumerd"
+static const char *help_msg =
+#ifdef LTTNG_EMBED_HELP
+#include <lttng-sessiond.8.h>
+#else
+NULL
+#endif
+;
 
 const char *progname;
-static 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. */
@@ -98,10 +100,9 @@ static int recv_child_signal;
  */
 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,
        .pid_mutex = PTHREAD_MUTEX_INITIALIZER,
        .lock = PTHREAD_MUTEX_INITIALIZER,
        .cond = PTHREAD_COND_INITIALIZER,
@@ -109,10 +110,9 @@ 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,
        .pid_mutex = PTHREAD_MUTEX_INITIALIZER,
        .lock = PTHREAD_MUTEX_INITIALIZER,
        .cond = PTHREAD_COND_INITIALIZER,
@@ -120,10 +120,9 @@ 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,
        .pid_mutex = PTHREAD_MUTEX_INITIALIZER,
        .lock = PTHREAD_MUTEX_INITIALIZER,
        .cond = PTHREAD_COND_INITIALIZER,
@@ -132,52 +131,45 @@ static struct consumer_data ustconsumer32_data = {
 
 /* Command line options */
 static const struct option long_options[] = {
-       { "client-sock", 1, 0, 'c' },
-       { "apps-sock", 1, 0, 'a' },
-       { "kconsumerd-cmd-sock", 1, 0, 'C' },
-       { "kconsumerd-err-sock", 1, 0, 'E' },
-       { "ustconsumerd32-cmd-sock", 1, 0, 'G' },
-       { "ustconsumerd32-err-sock", 1, 0, 'H' },
-       { "ustconsumerd64-cmd-sock", 1, 0, 'D' },
-       { "ustconsumerd64-err-sock", 1, 0, 'F' },
-       { "consumerd32-path", 1, 0, 'u' },
-       { "consumerd32-libdir", 1, 0, 'U' },
-       { "consumerd64-path", 1, 0, 't' },
-       { "consumerd64-libdir", 1, 0, 'T' },
-       { "daemonize", 0, 0, 'd' },
-       { "background", 0, 0, 'b' },
-       { "sig-parent", 0, 0, 'S' },
-       { "help", 0, 0, 'h' },
-       { "group", 1, 0, 'g' },
-       { "version", 0, 0, 'V' },
-       { "quiet", 0, 0, 'q' },
-       { "verbose", 0, 0, 'v' },
-       { "verbose-consumer", 0, 0, 'Z' },
-       { "no-kernel", 0, 0, 'N' },
-       { "pidfile", 1, 0, 'p' },
-       { "agent-tcp-port", 1, 0, 'J' },
-       { "config", 1, 0, 'f' },
-       { "load", 1, 0, 'l' },
-       { "kmod-probes", 1, 0, 'P' },
-       { "extra-kmod-probes", 1, 0, 'e' },
+       { "client-sock", required_argument, 0, 'c' },
+       { "apps-sock", required_argument, 0, 'a' },
+       { "kconsumerd-cmd-sock", required_argument, 0, '\0' },
+       { "kconsumerd-err-sock", required_argument, 0, '\0' },
+       { "ustconsumerd32-cmd-sock", required_argument, 0, '\0' },
+       { "ustconsumerd32-err-sock", required_argument, 0, '\0' },
+       { "ustconsumerd64-cmd-sock", required_argument, 0, '\0' },
+       { "ustconsumerd64-err-sock", required_argument, 0, '\0' },
+       { "consumerd32-path", required_argument, 0, '\0' },
+       { "consumerd32-libdir", required_argument, 0, '\0' },
+       { "consumerd64-path", required_argument, 0, '\0' },
+       { "consumerd64-libdir", required_argument, 0, '\0' },
+       { "daemonize", no_argument, 0, 'd' },
+       { "background", no_argument, 0, 'b' },
+       { "sig-parent", no_argument, 0, 'S' },
+       { "help", no_argument, 0, 'h' },
+       { "group", required_argument, 0, 'g' },
+       { "version", no_argument, 0, 'V' },
+       { "quiet", no_argument, 0, 'q' },
+       { "verbose", no_argument, 0, 'v' },
+       { "verbose-consumer", no_argument, 0, '\0' },
+       { "no-kernel", no_argument, 0, '\0' },
+       { "pidfile", required_argument, 0, 'p' },
+       { "agent-tcp-port", required_argument, 0, '\0' },
+       { "config", required_argument, 0, 'f' },
+       { "load", required_argument, 0, 'l' },
+       { "kmod-probes", required_argument, 0, '\0' },
+       { "extra-kmod-probes", required_argument, 0, '\0' },
        { NULL, 0, 0, 0 }
 };
 
+struct sessiond_config config;
+
 /* Command line options to ignore from configuration file */
 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;
@@ -209,6 +201,7 @@ 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;
 
 /*
  * UST registration command queue. This queue is tied with a futex and uses a N
@@ -236,15 +229,6 @@ 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";
 
 /*
@@ -281,20 +265,12 @@ 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 */
 
@@ -303,14 +279,26 @@ 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/health check requests.
+ * 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                3
+#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)
@@ -321,7 +309,7 @@ void sessiond_notify_ready(void)
                 * for client side.  This ppid is the one from the
                 * external process that spawned us.
                 */
-               if (opt_sig_parent) {
+               if (config.sig_parent) {
                        kill(ppid, SIGUSR1);
                }
 
@@ -329,65 +317,15 @@ void sessiond_notify_ready(void)
                 * Notify the parent of the fork() process that we are
                 * ready.
                 */
-               if (opt_daemon || opt_background) {
+               if (config.daemonize || config.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 = getenv("LTTNG_CONSUMERD32_BIN");
-       if (bin) {
-               consumerd32_bin = bin;
-       }
-       bin = getenv("LTTNG_CONSUMERD64_BIN");
-       if (bin) {
-               consumerd64_bin = bin;
-       }
-       libdir = getenv("LTTNG_CONSUMERD32_LIBDIR");
-       if (libdir) {
-               consumerd32_libdir = libdir;
-       }
-       libdir = getenv("LTTNG_CONSUMERD64_LIBDIR");
-       if (libdir) {
-               consumerd64_libdir = libdir;
-       }
-}
-
-/*
- * 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)
+int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
+               int *a_pipe)
 {
        int ret;
 
@@ -399,7 +337,7 @@ int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)
        }
 
        /* Add quit pipe */
-       ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
+       ret = lttng_poll_add(events, a_pipe[0], LPOLLIN | LPOLLERR);
        if (ret < 0) {
                goto error;
        }
@@ -411,17 +349,11 @@ error:
 }
 
 /*
- * Check if the thread quit pipe was triggered.
- *
- * Return 1 if it was triggered else 0;
+ * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
  */
-int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
+int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)
 {
-       if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
-               return 1;
-       }
-
-       return 0;
+       return __sessiond_set_thread_pollset(events, size, thread_quit_pipe);
 }
 
 /*
@@ -429,18 +361,18 @@ int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
  *
  * Return -1 on error or 0 if all pipes are created.
  */
-static int init_thread_quit_pipe(void)
+static int __init_thread_quit_pipe(int *a_pipe)
 {
        int ret, i;
 
-       ret = pipe(thread_quit_pipe);
+       ret = pipe(a_pipe);
        if (ret < 0) {
                PERROR("thread quit pipe");
                goto error;
        }
 
        for (i = 0; i < 2; i++) {
-               ret = fcntl(thread_quit_pipe[i], F_SETFD, FD_CLOEXEC);
+               ret = fcntl(a_pipe[i], F_SETFD, FD_CLOEXEC);
                if (ret < 0) {
                        PERROR("fcntl");
                        goto error;
@@ -451,6 +383,11 @@ error:
        return ret;
 }
 
+static int init_thread_quit_pipe(void)
+{
+       return __init_thread_quit_pipe(thread_quit_pipe);
+}
+
 /*
  * Stop all threads by closing the thread quit pipe.
  */
@@ -513,39 +450,62 @@ static void close_consumer_sockets(void)
                        PERROR("UST consumerd64 cmd_sock close");
                }
        }
+       if (kconsumer_data.channel_monitor_pipe >= 0) {
+               ret = close(kconsumer_data.channel_monitor_pipe);
+               if (ret < 0) {
+                       PERROR("kernel consumer channel monitor pipe close");
+               }
+       }
+       if (ustconsumer32_data.channel_monitor_pipe >= 0) {
+               ret = close(ustconsumer32_data.channel_monitor_pipe);
+               if (ret < 0) {
+                       PERROR("UST consumerd32 channel monitor pipe close");
+               }
+       }
+       if (ustconsumer64_data.channel_monitor_pipe >= 0) {
+               ret = close(ustconsumer64_data.channel_monitor_pipe);
+               if (ret < 0) {
+                       PERROR("UST consumerd64 channel monitor pipe close");
+               }
+       }
 }
 
 /*
- * Generate the full lock file path using the rundir.
+ * Wait on consumer process termination.
  *
- * Return the snprintf() return value thus a negative value is an error.
+ * Need to be called with the consumer data lock held or from a context
+ * ensuring no concurrent access to data (e.g: cleanup).
  */
-static int generate_lock_file_path(char *path, size_t len)
+static void wait_consumer(struct consumer_data *consumer_data)
 {
-       int ret;
+       pid_t ret;
+       int status;
 
-       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");
+       if (consumer_data->pid <= 0) {
+               return;
        }
 
-       return ret;
+       DBG("Waiting for complete teardown of consumerd (PID: %d)",
+                       consumer_data->pid);
+       ret = waitpid(consumer_data->pid, &status, 0);
+       if (ret == -1) {
+               PERROR("consumerd waitpid pid: %d", consumer_data->pid)
+       } else  if (!WIFEXITED(status)) {
+               ERR("consumerd termination with error: %d",
+                               WEXITSTATUS(ret));
+       }
+       consumer_data->pid = 0;
 }
 
 /*
- * Cleanup the daemon
+ * Cleanup the session daemon's data structures.
  */
-static void cleanup(void)
+static void sessiond_cleanup(void)
 {
        int ret;
        struct ltt_session *sess, *stmp;
-       char path[PATH_MAX];
 
-       DBG("Cleaning up");
+       DBG("Cleanup sessiond");
 
        /*
         * Close the thread quit pipe. It has already done its job,
@@ -554,68 +514,46 @@ static void cleanup(void)
        utils_close_pipe(thread_quit_pipe);
 
        /*
-        * If opt_pidfile is undefined, the default file will be wiped when
-        * removing the rundir.
+        * If config.pid_file_path.value is undefined, the default file will be
+        * wiped when removing the rundir.
         */
-       if (opt_pidfile) {
-               ret = remove(opt_pidfile);
+       if (config.pid_file_path.value) {
+               ret = remove(config.pid_file_path.value);
                if (ret < 0) {
-                       PERROR("remove pidfile %s", opt_pidfile);
+                       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);
+
+       DBG("Removing directory %s", config.kconsumerd_path.value);
+       (void) rmdir(config.kconsumerd_path.value);
 
        /* 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 %s", config.consumerd32_err_unix_sock_path.value);
+       (void) unlink(config.consumerd32_err_unix_sock_path.value);
+
+       DBG("Removing directory %s", config.consumerd32_path.value);
+       (void) rmdir(config.consumerd32_path.value);
 
        /* ust consumerd 64 */
-       snprintf(path, PATH_MAX,
-               DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH,
-               rundir);
-       DBG("Removing %s", path);
-       (void) unlink(path);
-
-       snprintf(path, PATH_MAX,
-               DEFAULT_USTCONSUMERD64_PATH,
-               rundir);
-       DBG("Removing directory %s", path);
-       (void) rmdir(path);
+       DBG("Removing %s", config.consumerd64_err_unix_sock_path.value);
+       (void) unlink(config.consumerd64_err_unix_sock_path.value);
+
+       DBG("Removing directory %s", config.consumerd64_path.value);
+       (void) rmdir(config.consumerd64_path.value);
 
        DBG("Cleaning up all sessions");
 
@@ -630,11 +568,18 @@ static void cleanup(void)
                }
        }
 
+       wait_consumer(&kconsumer_data);
+       wait_consumer(&ustconsumer64_data);
+       wait_consumer(&ustconsumer32_data);
+
+       DBG("Cleaning up all agent apps");
+       agent_app_ht_clean();
+
        DBG("Closing all UST sockets");
        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);
@@ -649,34 +594,6 @@ static void cleanup(void)
 
        close_consumer_sockets();
 
-       /*
-        * 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);
-       }
-
-       if (opt_pidfile) {
-               free(opt_pidfile);
-       }
-
-       if (opt_load_session_path) {
-               free(opt_load_session_path);
-       }
-
        if (load_info) {
                load_session_destroy_data(load_info);
                free(load_info);
@@ -687,18 +604,13 @@ static void cleanup(void)
         * 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");
-                       }
+               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");
                }
        }
 
@@ -707,14 +619,18 @@ static void cleanup(void)
         * using it, for instance lttng-relayd, which can start in
         * parallel with this teardown.
         */
+}
+
+/*
+ * Cleanup the daemon's option data structures.
+ */
+static void sessiond_cleanup_options(void)
+{
+       DBG("Cleaning up options");
 
-       free(rundir);
+       sessiond_config_fini(&config);
 
-       /* <fun> */
-       DBG("%c[%d;%dm*** assert failed :-) *** ==> %c[%dm%c[%d;%dm"
-                       "Matthew, BEET driven development works!%c[%dm",
-                       27, 1, 31, 27, 0, 27, 1, 33, 27, 0);
-       /* </fun> */
+       run_as_destroy_worker();
 }
 
 /*
@@ -760,7 +676,7 @@ 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;
        }
@@ -780,34 +696,57 @@ error:
  * right amount of memory and copying the original information from the lsm
  * structure.
  *
- * Return total size of the buffer pointed by buf.
+ * Return 0 on success, negative value on error.
  */
-static int setup_lttng_msg(struct command_ctx *cmd_ctx, size_t size)
+static int setup_lttng_msg(struct command_ctx *cmd_ctx,
+       const void *payload_buf, size_t payload_len,
+       const void *cmd_header_buf, size_t cmd_header_len)
 {
-       int ret, buf_size;
+       int ret = 0;
+       const size_t header_len = sizeof(struct lttcomm_lttng_msg);
+       const size_t cmd_header_offset = header_len;
+       const size_t payload_offset = cmd_header_offset + cmd_header_len;
+       const size_t total_msg_size = header_len + cmd_header_len + payload_len;
 
-       buf_size = size;
+       cmd_ctx->llm = zmalloc(total_msg_size);
 
-       cmd_ctx->llm = zmalloc(sizeof(struct lttcomm_lttng_msg) + buf_size);
        if (cmd_ctx->llm == NULL) {
                PERROR("zmalloc");
                ret = -ENOMEM;
-               goto error;
+               goto end;
        }
 
        /* Copy common data */
        cmd_ctx->llm->cmd_type = cmd_ctx->lsm->cmd_type;
        cmd_ctx->llm->pid = cmd_ctx->lsm->domain.attr.pid;
+       cmd_ctx->llm->cmd_header_size = cmd_header_len;
+       cmd_ctx->llm->data_size = payload_len;
+       cmd_ctx->lttng_msg_size = total_msg_size;
 
-       cmd_ctx->llm->data_size = size;
-       cmd_ctx->lttng_msg_size = sizeof(struct lttcomm_lttng_msg) + buf_size;
+       /* Copy command header */
+       if (cmd_header_len) {
+               memcpy(((uint8_t *) cmd_ctx->llm) + cmd_header_offset, cmd_header_buf,
+                       cmd_header_len);
+       }
 
-       return buf_size;
+       /* Copy payload */
+       if (payload_len) {
+               memcpy(((uint8_t *) cmd_ctx->llm) + payload_offset, payload_buf,
+                       payload_len);
+       }
 
-error:
+end:
        return ret;
 }
 
+/*
+ * Version of setup_lttng_msg() without command header.
+ */
+static int setup_lttng_msg_no_cmd_header(struct command_ctx *cmd_ctx,
+       void *payload_buf, size_t payload_len)
+{
+       return setup_lttng_msg(cmd_ctx, payload_buf, payload_len, NULL, 0);
+}
 /*
  * Update the kernel poll set of all channel fd available over all tracing
  * session. Add the wakeup pipe at the end of the set.
@@ -873,42 +812,47 @@ static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
                }
                ksess = session->kernel_session;
 
-               cds_list_for_each_entry(channel, &ksess->channel_list.head, list) {
-                       if (channel->fd == fd) {
-                               DBG("Channel found, updating kernel streams");
-                               ret = kernel_open_channel_stream(channel);
-                               if (ret < 0) {
-                                       goto error;
-                               }
-                               /* Update the stream global counter */
-                               ksess->stream_count_global += ret;
+               cds_list_for_each_entry(channel,
+                               &ksess->channel_list.head, list) {
+                       struct lttng_ht_iter iter;
+                       struct consumer_socket *socket;
 
-                               /*
-                                * Have we already sent fds to the consumer? If yes, it means
-                                * that tracing is started so it is safe to send our updated
-                                * stream fds.
-                                */
-                               if (ksess->consumer_fds_sent == 1 && ksess->consumer != NULL) {
-                                       struct lttng_ht_iter iter;
-                                       struct consumer_socket *socket;
-
-                                       rcu_read_lock();
-                                       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,
-                                                               channel, ksess,
-                                                               session->output_traces ? 1 : 0);
-                                               pthread_mutex_unlock(socket->lock);
-                                               if (ret < 0) {
-                                                       rcu_read_unlock();
-                                                       goto error;
-                                               }
-                                       }
+                       if (channel->fd != fd) {
+                               continue;
+                       }
+                       DBG("Channel found, updating kernel streams");
+                       ret = kernel_open_channel_stream(channel);
+                       if (ret < 0) {
+                               goto error;
+                       }
+                       /* Update the stream global counter */
+                       ksess->stream_count_global += ret;
+
+                       /*
+                        * Have we already sent fds to the consumer? If yes, it
+                        * means that tracing is started so it is safe to send
+                        * our updated stream fds.
+                        */
+                       if (ksess->consumer_fds_sent != 1
+                                       || ksess->consumer == NULL) {
+                               ret = -1;
+                               goto error;
+                       }
+
+                       rcu_read_lock();
+                       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,
+                                               channel, ksess,
+                                               session->output_traces ? 1 : 0);
+                               pthread_mutex_unlock(socket->lock);
+                               if (ret < 0) {
                                        rcu_read_unlock();
+                                       goto error;
                                }
-                               goto error;
                        }
+                       rcu_read_unlock();
                }
                session_unlock(session);
        }
@@ -937,10 +881,30 @@ 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) {
+               struct ust_app *app;
+
                session_lock(sess);
-               if (sess->ust_session) {
-                       ust_app_global_update(sess->ust_session, app_sock);
+               if (!sess->ust_session) {
+                       goto unlock_session;
                }
+
+               rcu_read_lock();
+               assert(app_sock >= 0);
+               app = ust_app_find_by_sock(app_sock);
+               if (app == NULL) {
+                       /*
+                        * Application can be unregistered before so
+                        * this is possible hence simply stopping the
+                        * update.
+                        */
+                       DBG3("UST app update failed to find app sock %d",
+                               app_sock);
+                       goto unlock_rcu;
+               }
+               ust_app_global_update(sess->ust_session, app);
+       unlock_rcu:
+               rcu_read_unlock();
+       unlock_session:
                session_unlock(sess);
        }
 }
@@ -1003,12 +967,14 @@ static void *thread_manage_kernel(void *data)
                        update_poll_flag = 0;
                }
 
-               DBG("Thread kernel polling on %d fds", LTTNG_POLL_GETNB(&events));
+               DBG("Thread kernel polling");
 
                /* Poll infinite value of time */
        restart:
                health_poll_entry();
                ret = lttng_poll_wait(&events, -1);
+               DBG("Thread kernel return from poll on %d fds",
+                               LTTNG_POLL_GETNB(&events));
                health_poll_exit();
                if (ret < 0) {
                        /*
@@ -1034,6 +1000,11 @@ static void *thread_manage_kernel(void *data)
 
                        health_code_update();
 
+                       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) {
@@ -1042,31 +1013,33 @@ static void *thread_manage_kernel(void *data)
                        }
 
                        /* Check for data on kernel pipe */
-                       if (pollfd == kernel_poll_pipe[0] && (revents & LPOLLIN)) {
-                               (void) lttng_read(kernel_poll_pipe[0],
-                                       &tmp, 1);
-                               /*
-                                * Ret value is useless here, if this pipe gets any actions an
-                                * update is required anyway.
-                                */
-                               update_poll_flag = 1;
-                               continue;
-                       } else {
-                               /*
-                                * New CPU detected by the kernel. Adding kernel stream to
-                                * kernel session and updating the kernel consumer
-                                */
-                               if (revents & LPOLLIN) {
+                       if (revents & LPOLLIN) {
+                               if (pollfd == kernel_poll_pipe[0]) {
+                                       (void) lttng_read(kernel_poll_pipe[0],
+                                               &tmp, 1);
+                                       /*
+                                        * Ret value is useless here, if this pipe gets any actions an
+                                        * update is required anyway.
+                                        */
+                                       update_poll_flag = 1;
+                                       continue;
+                               } else {
+                                       /*
+                                        * New CPU detected by the kernel. Adding kernel stream to
+                                        * kernel session and updating the kernel consumer
+                                        */
                                        ret = update_kernel_stream(&kconsumer_data, pollfd);
                                        if (ret < 0) {
                                                continue;
                                        }
                                        break;
-                                       /*
-                                        * TODO: We might want to handle the LPOLLERR | LPOLLHUP
-                                        * and unregister kernel stream at this point.
-                                        */
                                }
+                       } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               update_poll_flag = 1;
+                               continue;
+                       } else {
+                               ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                               goto error;
                        }
                }
        }
@@ -1122,9 +1095,13 @@ static void *thread_manage_consumer(void *data)
        enum lttcomm_return_code code;
        struct lttng_poll_event events;
        struct consumer_data *consumer_data = data;
+       struct consumer_socket *cmd_socket_wrapper = NULL;
 
        DBG("[thread] Manage consumer started");
 
+       rcu_register_thread();
+       rcu_thread_online();
+
        health_register(health_sessiond, HEALTH_SESSIOND_TYPE_CONSUMER);
 
        health_code_update();
@@ -1179,6 +1156,11 @@ restart:
 
                health_code_update();
 
+               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) {
@@ -1188,9 +1170,14 @@ restart:
 
                /* Event on the registration socket */
                if (pollfd == consumer_data->err_sock) {
-                       if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                       if (revents & LPOLLIN) {
+                               continue;
+                       } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
                                ERR("consumer err socket poll error");
                                goto error;
+                       } else {
+                               ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                               goto error;
                        }
                }
        }
@@ -1218,40 +1205,43 @@ restart:
        }
 
        health_code_update();
-       if (code == LTTCOMM_CONSUMERD_COMMAND_SOCK_READY) {
-               /* Connect both socket, command and metadata. */
-               consumer_data->cmd_sock =
-                       lttcomm_connect_unix_sock(consumer_data->cmd_unix_sock_path);
-               consumer_data->metadata_fd =
-                       lttcomm_connect_unix_sock(consumer_data->cmd_unix_sock_path);
-               if (consumer_data->cmd_sock < 0
-                               || consumer_data->metadata_fd < 0) {
-                       PERROR("consumer connect cmd socket");
-                       /* On error, signal condition and quit. */
-                       signal_consumer_condition(consumer_data, -1);
-                       goto error;
-               }
-               consumer_data->metadata_sock.fd_ptr = &consumer_data->metadata_fd;
-               /* Create metadata socket lock. */
-               consumer_data->metadata_sock.lock = zmalloc(sizeof(pthread_mutex_t));
-               if (consumer_data->metadata_sock.lock == NULL) {
-                       PERROR("zmalloc pthread mutex");
-                       ret = -1;
-                       goto error;
-               }
-               pthread_mutex_init(consumer_data->metadata_sock.lock, NULL);
-
-               signal_consumer_condition(consumer_data, 1);
-               DBG("Consumer command socket ready (fd: %d", consumer_data->cmd_sock);
-               DBG("Consumer metadata socket ready (fd: %d)",
-                               consumer_data->metadata_fd);
-       } else {
+       if (code != LTTCOMM_CONSUMERD_COMMAND_SOCK_READY) {
                ERR("consumer error when waiting for SOCK_READY : %s",
                                lttcomm_get_readable_code(-code));
                goto error;
        }
 
-       /* Remove the consumerd error sock since we've established a connexion */
+       /* Connect both command and metadata sockets. */
+       consumer_data->cmd_sock =
+                       lttcomm_connect_unix_sock(
+                               consumer_data->cmd_unix_sock_path);
+       consumer_data->metadata_fd =
+                       lttcomm_connect_unix_sock(
+                               consumer_data->cmd_unix_sock_path);
+       if (consumer_data->cmd_sock < 0 || consumer_data->metadata_fd < 0) {
+               PERROR("consumer connect cmd socket");
+               /* On error, signal condition and quit. */
+               signal_consumer_condition(consumer_data, -1);
+               goto error;
+       }
+
+       consumer_data->metadata_sock.fd_ptr = &consumer_data->metadata_fd;
+
+       /* Create metadata socket lock. */
+       consumer_data->metadata_sock.lock = zmalloc(sizeof(pthread_mutex_t));
+       if (consumer_data->metadata_sock.lock == NULL) {
+               PERROR("zmalloc pthread mutex");
+               goto error;
+       }
+       pthread_mutex_init(consumer_data->metadata_sock.lock, NULL);
+
+       DBG("Consumer command socket ready (fd: %d", consumer_data->cmd_sock);
+       DBG("Consumer metadata socket ready (fd: %d)",
+                       consumer_data->metadata_fd);
+
+       /*
+        * Remove the consumerd error sock since we've established a connection.
+        */
        ret = lttng_poll_del(&events, consumer_data->err_sock);
        if (ret < 0) {
                goto error;
@@ -1272,6 +1262,27 @@ restart:
 
        health_code_update();
 
+       /*
+        * Transfer the write-end of the channel monitoring pipe to the
+        * by issuing a SET_CHANNEL_MONITOR_PIPE command.
+        */
+       cmd_socket_wrapper = consumer_allocate_socket(&consumer_data->cmd_sock);
+       if (!cmd_socket_wrapper) {
+               goto error;
+       }
+
+       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;
+
+       /* The thread is completely initialized, signal that it is ready. */
+       signal_consumer_condition(consumer_data, 1);
+
        /* Infinite blocking call, waiting for transmission */
 restart_poll:
        while (1) {
@@ -1306,6 +1317,11 @@ restart_poll:
 
                        health_code_update();
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /*
                         * Thread quit pipe has been triggered, flag that we should stop
                         * but continue the current loop to handle potential data from
@@ -1315,7 +1331,8 @@ restart_poll:
 
                        if (pollfd == sock) {
                                /* Event on the consumerd socket */
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)
+                                               && !(revents & LPOLLIN)) {
                                        ERR("consumer err socket second poll error");
                                        goto error;
                                }
@@ -1333,6 +1350,11 @@ restart_poll:
 
                                goto exit;
                        } else if (pollfd == consumer_data->metadata_fd) {
+                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)
+                                               && !(revents & LPOLLIN)) {
+                                       ERR("consumer err metadata socket second poll error");
+                                       goto error;
+                               }
                                /* UST metadata requests */
                                ret = ust_consumer_metadata_request(
                                                &consumer_data->metadata_sock);
@@ -1396,7 +1418,6 @@ error:
 
        unlink(consumer_data->err_unix_sock_path);
        unlink(consumer_data->cmd_unix_sock_path);
-       consumer_data->pid = 0;
        pthread_mutex_unlock(&consumer_data->lock);
 
        /* Cleanup metadata socket mutex. */
@@ -1405,6 +1426,10 @@ error:
                free(consumer_data->metadata_sock.lock);
        }
        lttng_poll_clean(&events);
+
+       if (cmd_socket_wrapper) {
+               consumer_destroy_socket(cmd_socket_wrapper);
+       }
 error_poll:
        if (err) {
                health_error();
@@ -1413,6 +1438,9 @@ error_poll:
        health_unregister(health_sessiond);
        DBG("consumer thread cleanup completed");
 
+       rcu_thread_offline();
+       rcu_unregister_thread();
+
        return NULL;
 }
 
@@ -1456,12 +1484,14 @@ static void *thread_manage_apps(void *data)
        health_code_update();
 
        while (1) {
-               DBG("Apps thread polling on %d fds", LTTNG_POLL_GETNB(&events));
+               DBG("Apps thread polling");
 
                /* Inifinite blocking call, waiting for transmission */
        restart:
                health_poll_entry();
                ret = lttng_poll_wait(&events, -1);
+               DBG("Apps thread return from poll on %d fds",
+                               LTTNG_POLL_GETNB(&events));
                health_poll_exit();
                if (ret < 0) {
                        /*
@@ -1482,6 +1512,11 @@ static void *thread_manage_apps(void *data)
 
                        health_code_update();
 
+                       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) {
@@ -1491,10 +1526,7 @@ static void *thread_manage_apps(void *data)
 
                        /* Inspect the apps cmd pipe */
                        if (pollfd == apps_cmd_pipe[0]) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
-                                       ERR("Apps command pipe error");
-                                       goto error;
-                               } else if (revents & LPOLLIN) {
+                               if (revents & LPOLLIN) {
                                        int sock;
 
                                        /* Empty pipe */
@@ -1507,9 +1539,8 @@ static void *thread_manage_apps(void *data)
                                        health_code_update();
 
                                        /*
-                                        * We only monitor the error events of the socket. This
-                                        * thread does not handle any incoming data from UST
-                                        * (POLLIN).
+                                        * Since this is a command socket (write then read),
+                                        * we only monitor the error events of the socket.
                                         */
                                        ret = lttng_poll_add(&events, sock,
                                                        LPOLLERR | LPOLLHUP | LPOLLRDHUP);
@@ -1518,6 +1549,12 @@ static void *thread_manage_apps(void *data)
                                        }
 
                                        DBG("Apps with sock %d added to poll set", sock);
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                                       ERR("Apps command pipe error");
+                                       goto error;
+                               } else {
+                                       ERR("Unknown poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        } else {
                                /*
@@ -1533,6 +1570,9 @@ static void *thread_manage_apps(void *data)
 
                                        /* Socket closed on remote end. */
                                        ust_app_unregister(pollfd);
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
 
@@ -1660,6 +1700,11 @@ static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
                uint32_t revents = LTTNG_POLL_GETEV(&events, i);
                int pollfd = LTTNG_POLL_GETFD(&events, i);
 
+               if (!revents) {
+                       /* No activity for this FD (poll implementation). */
+                       continue;
+               }
+
                cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
                                &wait_queue->head, head) {
                        if (pollfd == wait_node->app->sock &&
@@ -1668,7 +1713,16 @@ static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
                                wait_queue->count--;
                                ust_app_destroy(wait_node->app);
                                free(wait_node);
+                               /*
+                                * Silence warning of use-after-free in
+                                * cds_list_for_each_entry_safe which uses
+                                * __typeof__(*wait_node).
+                                */
+                               wait_node = NULL;
                                break;
+                       } else {
+                               ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                               goto error;
                        }
                }
        }
@@ -1702,6 +1756,8 @@ static void *thread_dispatch_ust_registration(void *data)
                .count = 0,
        };
 
+       rcu_register_thread();
+
        health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH);
 
        if (testpoint(sessiond_thread_app_reg_dispatch)) {
@@ -1714,12 +1770,16 @@ static void *thread_dispatch_ust_registration(void *data)
 
        DBG("[thread] Dispatch UST command started");
 
-       while (!CMM_LOAD_SHARED(dispatch_thread_exit)) {
+       for (;;) {
                health_code_update();
 
                /* Atomically prepare the queue futex */
                futex_nto1_prepare(&ust_cmd_queue.futex);
 
+               if (CMM_LOAD_SHARED(dispatch_thread_exit)) {
+                       break;
+               }
+
                do {
                        struct ust_app *app = NULL;
                        ust_cmd = NULL;
@@ -1870,7 +1930,7 @@ static void *thread_dispatch_ust_registration(void *data)
                                 * Don't care about return value. Let the manage apps threads
                                 * handle app unregistration upon socket close.
                                 */
-                               (void) ust_app_register_done(app->sock);
+                               (void) ust_app_register_done(app);
 
                                /*
                                 * Even if the application socket has been closed, send the app
@@ -1912,6 +1972,22 @@ error:
                free(wait_node);
        }
 
+       /* Empty command queue. */
+       for (;;) {
+               /* Dequeue command for registration */
+               node = cds_wfcq_dequeue_blocking(&ust_cmd_queue.head, &ust_cmd_queue.tail);
+               if (node == NULL) {
+                       break;
+               }
+               ust_cmd = caa_container_of(node, struct ust_command, node);
+               ret = close(ust_cmd->sock);
+               if (ret < 0) {
+                       PERROR("close ust sock exit dispatch %d", ust_cmd->sock);
+               }
+               lttng_fd_put(LTTNG_FD_APPS, 1);
+               free(ust_cmd);
+       }
+
 error_testpoint:
        DBG("Dispatch thread dying");
        if (err) {
@@ -1919,6 +1995,7 @@ error_testpoint:
                ERR("Health error occurred in %s", __func__);
        }
        health_unregister(health_sessiond);
+       rcu_unregister_thread();
        return NULL;
 }
 
@@ -1999,6 +2076,11 @@ static void *thread_registration_apps(void *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) {
@@ -2008,10 +2090,7 @@ static void *thread_registration_apps(void *data)
 
                        /* Event on the registration socket */
                        if (pollfd == apps_sock) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
-                                       ERR("Register apps socket poll error");
-                                       goto error;
-                               } else if (revents & LPOLLIN) {
+                               if (revents & LPOLLIN) {
                                        sock = lttcomm_accept_unix_sock(apps_sock);
                                        if (sock < 0) {
                                                goto error;
@@ -2024,10 +2103,12 @@ static void *thread_registration_apps(void *data)
                                         * lttcomm_setsockopt_snd_timeout expect msec as
                                         * parameter.
                                         */
-                                       (void) lttcomm_setsockopt_rcv_timeout(sock,
-                                                       app_socket_timeout * 1000);
-                                       (void) lttcomm_setsockopt_snd_timeout(sock,
-                                                       app_socket_timeout * 1000);
+                                       if (config.app_socket_timeout >= 0) {
+                                               (void) lttcomm_setsockopt_rcv_timeout(sock,
+                                                               config.app_socket_timeout * 1000);
+                                               (void) lttcomm_setsockopt_snd_timeout(sock,
+                                                               config.app_socket_timeout * 1000);
+                                       }
 
                                        /*
                                         * Set the CLOEXEC flag. Return code is useless because
@@ -2039,6 +2120,10 @@ static void *thread_registration_apps(void *data)
                                        ust_cmd = zmalloc(sizeof(struct ust_command));
                                        if (ust_cmd == NULL) {
                                                PERROR("ust command zmalloc");
+                                               ret = close(sock);
+                                               if (ret) {
+                                                       PERROR("close");
+                                               }
                                                goto error;
                                        }
 
@@ -2094,6 +2179,12 @@ static void *thread_registration_apps(void *data)
                                         * barrier with the exchange in cds_wfcq_enqueue.
                                         */
                                        futex_nto1_wake(&ust_cmd_queue.futex);
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                                       ERR("Register apps socket poll error");
+                                       goto error;
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
                }
@@ -2117,7 +2208,7 @@ 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);
@@ -2143,12 +2234,17 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
        int ret, clock_ret;
        struct timespec timeout;
 
-       /* Make sure we set the readiness flag to 0 because we are NOT ready */
+       /*
+        * Make sure we set the readiness flag to 0 because we are NOT ready.
+        * This access to consumer_thread_is_ready does not need to be
+        * protected by consumer_data.cond_mutex (yet) since the consumer
+        * management thread has not been started at this point.
+        */
        consumer_data->consumer_thread_is_ready = 0;
 
        /* Setup pthread condition */
        ret = pthread_condattr_init(&consumer_data->condattr);
-       if (ret != 0) {
+       if (ret) {
                errno = ret;
                PERROR("pthread_condattr_init consumer data");
                goto error;
@@ -2160,22 +2256,23 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
         * for a more details and how we noticed it.
         */
        ret = pthread_condattr_setclock(&consumer_data->condattr, CLOCK_MONOTONIC);
-       if (ret != 0) {
+       if (ret) {
                errno = ret;
                PERROR("pthread_condattr_setclock consumer data");
                goto error;
        }
 
        ret = pthread_cond_init(&consumer_data->cond, &consumer_data->condattr);
-       if (ret != 0) {
+       if (ret) {
                errno = ret;
                PERROR("pthread_cond_init consumer data");
                goto error;
        }
 
-       ret = pthread_create(&consumer_data->thread, NULL, thread_manage_consumer,
-                       consumer_data);
-       if (ret != 0) {
+       ret = pthread_create(&consumer_data->thread, default_pthread_attr(),
+                       thread_manage_consumer, consumer_data);
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create consumer");
                ret = -1;
                goto error;
@@ -2185,7 +2282,7 @@ static int spawn_consumer_thread(struct consumer_data *consumer_data)
        pthread_mutex_lock(&consumer_data->cond_mutex);
 
        /* Get time for sem_timedwait absolute timeout */
-       clock_ret = clock_gettime(CLOCK_MONOTONIC, &timeout);
+       clock_ret = lttng_clock_gettime(CLOCK_MONOTONIC, &timeout);
        /*
         * Set the timeout for the condition timed wait even if the clock gettime
         * call fails since we might loop on that call and we want to avoid to
@@ -2271,7 +2368,7 @@ static int join_consumer_thread(struct consumer_data *consumer_data)
                int ret;
                ret = kill(consumer_data->pid, SIGTERM);
                if (ret) {
-                       ERR("Error killing consumer daemon");
+                       PERROR("Error killing consumer daemon");
                        return ret;
                }
                return pthread_join(consumer_data->thread, &status);
@@ -2300,7 +2397,7 @@ 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";
@@ -2316,52 +2413,52 @@ 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);
+                       DBG3("  2) %s/%s", INSTALL_BIN_PATH, DEFAULT_CONSUMERD_FILE);
+                       DBG3("  3) %s", config.consumerd32_bin_path.value);
+                       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 (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[0] != '\0') {
                                char *tmp;
                                size_t tmplen;
 
-                               tmp = getenv("LD_LIBRARY_PATH");
+                               tmp = lttng_secure_getenv("LD_LIBRARY_PATH");
                                if (!tmp) {
                                        tmp = "";
                                }
                                tmplen = strlen("LD_LIBRARY_PATH=")
-                                       + strlen(consumerd64_libdir) + 1 /* : */ + strlen(tmp);
+                                       + 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);
@@ -2373,13 +2470,13 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                        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') {
+                       if (config.consumerd64_lib_dir.value[0] != '\0') {
                                free(tmpnew);
                        }
                        break;
@@ -2388,23 +2485,23 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                {
                        char *tmpnew = NULL;
 
-                       if (consumerd32_libdir[0] != '\0') {
+                       if (config.consumerd32_lib_dir.value[0] != '\0') {
                                char *tmp;
                                size_t tmplen;
 
-                               tmp = getenv("LD_LIBRARY_PATH");
+                               tmp = lttng_secure_getenv("LD_LIBRARY_PATH");
                                if (!tmp) {
                                        tmp = "";
                                }
                                tmplen = strlen("LD_LIBRARY_PATH=")
-                                       + strlen(consumerd32_libdir) + 1 /* : */ + strlen(tmp);
+                                       + 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);
@@ -2416,13 +2513,13 @@ static pid_t spawn_consumerd(struct consumer_data *consumer_data)
                                        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') {
+                       if (config.consumerd32_lib_dir.value[0] != '\0') {
                                free(tmpnew);
                        }
                        break;
@@ -2521,7 +2618,6 @@ 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;
        }
 
@@ -2536,6 +2632,18 @@ static int init_kernel_tracer(void)
                goto error_modules;
        }
 
+       ret = kernel_supports_ring_buffer_snapshot_sample_positions(
+                       kernel_tracer_fd);
+       if (ret < 0) {
+               goto error_modules;
+       }
+
+       if (ret < 1) {
+               WARN("Kernel tracer does not support buffer monitoring. "
+                       "The monitoring timer of channels in the kernel domain "
+                       "will be set to 0 (disabled).");
+       }
+
        DBG("Kernel tracer fd %d", kernel_tracer_fd);
        return 0;
 
@@ -2594,7 +2702,7 @@ static int copy_session_consumer(int domain, struct ltt_session *session)
                 * domain.
                 */
                if (session->kernel_session->consumer) {
-                       consumer_destroy_output(session->kernel_session->consumer);
+                       consumer_output_put(session->kernel_session->consumer);
                }
                session->kernel_session->consumer =
                        consumer_copy_output(session->consumer);
@@ -2608,7 +2716,7 @@ static int copy_session_consumer(int domain, struct ltt_session *session)
        case LTTNG_DOMAIN_UST:
                DBG3("Copying tracing session consumer output in UST session");
                if (session->ust_session->consumer) {
-                       consumer_destroy_output(session->ust_session->consumer);
+                       consumer_output_put(session->ust_session->consumer);
                }
                session->ust_session->consumer =
                        consumer_copy_output(session->consumer);
@@ -2673,7 +2781,16 @@ static int create_ust_session(struct ltt_session *session,
        lus->snapshot_mode = session->snapshot_mode;
        lus->live_timer_interval = session->live_timer;
        session->ust_session = lus;
-
+       if (session->shm_path[0]) {
+               strncpy(lus->root_shm_path, session->shm_path,
+                       sizeof(lus->root_shm_path));
+               lus->root_shm_path[sizeof(lus->root_shm_path) - 1] = '\0';
+               strncpy(lus->shm_path, session->shm_path,
+                       sizeof(lus->shm_path));
+               lus->shm_path[sizeof(lus->shm_path) - 1] = '\0';
+               strncat(lus->shm_path, "/ust",
+                       sizeof(lus->shm_path) - strlen(lus->shm_path) - 1);
+       }
        /* Copy session output to the newly created UST session */
        ret = copy_session_consumer(domain->type, session);
        if (ret != LTTNG_OK) {
@@ -2719,7 +2836,7 @@ static int create_kernel_session(struct ltt_session *session)
                                session->kernel_session->consumer->dst.trace_path,
                                S_IRWXU | S_IRWXG, session->uid, session->gid);
                if (ret < 0) {
-                       if (ret != -EEXIST) {
+                       if (errno != EEXIST) {
                                ERR("Trace directory creation error");
                                goto error;
                        }
@@ -2781,6 +2898,8 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
 
        DBG("Processing client command %d", cmd_ctx->lsm->cmd_type);
 
+       assert(!rcu_read_ongoing());
+
        *sock_error = 0;
 
        switch (cmd_ctx->lsm->cmd_type) {
@@ -2798,13 +2917,18 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_SNAPSHOT_LIST_OUTPUT:
        case LTTNG_SNAPSHOT_RECORD:
        case LTTNG_SAVE_SESSION:
+       case LTTNG_SET_SESSION_SHM_PATH:
+       case LTTNG_REGENERATE_METADATA:
+       case LTTNG_REGENERATE_STATEDUMP:
+       case LTTNG_REGISTER_TRIGGER:
+       case LTTNG_UNREGISTER_TRIGGER:
                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;
@@ -2838,10 +2962,12 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_LIST_CHANNELS:
        case LTTNG_LIST_EVENTS:
        case LTTNG_LIST_SYSCALLS:
+       case LTTNG_LIST_TRACKER_PIDS:
+       case LTTNG_DATA_PENDING:
                break;
        default:
                /* Setup lttng message with no payload */
-               ret = setup_lttng_msg(cmd_ctx, 0);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0);
                if (ret < 0) {
                        /* This label does not try to unlock the session */
                        goto init_setup_error;
@@ -2853,12 +2979,13 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_CREATE_SESSION:
        case LTTNG_CREATE_SESSION_SNAPSHOT:
        case LTTNG_CREATE_SESSION_LIVE:
-       case LTTNG_CALIBRATE:
        case LTTNG_LIST_SESSIONS:
        case LTTNG_LIST_TRACEPOINTS:
        case LTTNG_LIST_SYSCALLS:
        case LTTNG_LIST_TRACEPOINT_FIELDS:
        case LTTNG_SAVE_SESSION:
+       case LTTNG_REGISTER_TRIGGER:
+       case LTTNG_UNREGISTER_TRIGGER:
                need_tracing_session = 0;
                break;
        default:
@@ -3007,7 +3134,7 @@ 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);
@@ -3036,7 +3163,7 @@ 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);
@@ -3074,6 +3201,8 @@ skip_domain:
        if (cmd_ctx->lsm->cmd_type == LTTNG_START_TRACE ||
                        cmd_ctx->lsm->cmd_type == LTTNG_STOP_TRACE) {
                switch (cmd_ctx->lsm->domain.type) {
+               case LTTNG_DOMAIN_NONE:
+                       break;
                case LTTNG_DOMAIN_JUL:
                case LTTNG_DOMAIN_LOG4J:
                case LTTNG_DOMAIN_PYTHON:
@@ -3089,6 +3218,9 @@ skip_domain:
                                goto error;
                        }
                        break;
+               default:
+                       ret = LTTNG_ERR_UNKNOWN_DOMAIN;
+                       goto error;
                }
        }
 
@@ -3124,9 +3256,74 @@ skip_domain:
        switch (cmd_ctx->lsm->cmd_type) {
        case LTTNG_ADD_CONTEXT:
        {
-               ret = cmd_add_context(cmd_ctx->session, cmd_ctx->lsm->domain.type,
+               /*
+                * An LTTNG_ADD_CONTEXT command might have a supplementary
+                * payload if the context being added is an application context.
+                */
+               if (cmd_ctx->lsm->u.context.ctx.ctx ==
+                               LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
+                       char *provider_name = NULL, *context_name = NULL;
+                       size_t provider_name_len =
+                                       cmd_ctx->lsm->u.context.provider_name_len;
+                       size_t context_name_len =
+                                       cmd_ctx->lsm->u.context.context_name_len;
+
+                       if (provider_name_len == 0 || context_name_len == 0) {
+                               /*
+                                * Application provider and context names MUST
+                                * be provided.
+                                */
+                               ret = -LTTNG_ERR_INVALID;
+                               goto error;
+                       }
+
+                       provider_name = zmalloc(provider_name_len + 1);
+                       if (!provider_name) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto error;
+                       }
+                       cmd_ctx->lsm->u.context.ctx.u.app_ctx.provider_name =
+                                       provider_name;
+
+                       context_name = zmalloc(context_name_len + 1);
+                       if (!context_name) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto error_add_context;
+                       }
+                       cmd_ctx->lsm->u.context.ctx.u.app_ctx.ctx_name =
+                                       context_name;
+
+                       ret = lttcomm_recv_unix_sock(sock, provider_name,
+                                       provider_name_len);
+                       if (ret < 0) {
+                               goto error_add_context;
+                       }
+
+                       ret = lttcomm_recv_unix_sock(sock, context_name,
+                                       context_name_len);
+                       if (ret < 0) {
+                               goto error_add_context;
+                       }
+               }
+
+               /*
+                * cmd_add_context assumes ownership of the provider and context
+                * names.
+                */
+               ret = cmd_add_context(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type,
                                cmd_ctx->lsm->u.context.channel_name,
-                               &cmd_ctx->lsm->u.context.ctx, kernel_poll_pipe[1]);
+                               &cmd_ctx->lsm->u.context.ctx,
+                               kernel_poll_pipe[1]);
+
+               cmd_ctx->lsm->u.context.ctx.u.app_ctx.provider_name = NULL;
+               cmd_ctx->lsm->u.context.ctx.u.app_ctx.ctx_name = NULL;
+error_add_context:
+               free(cmd_ctx->lsm->u.context.ctx.u.app_ctx.provider_name);
+               free(cmd_ctx->lsm->u.context.ctx.u.app_ctx.ctx_name);
+               if (ret < 0) {
+                       goto error;
+               }
                break;
        }
        case LTTNG_DISABLE_CHANNEL:
@@ -3137,8 +3334,34 @@ skip_domain:
        }
        case LTTNG_DISABLE_EVENT:
        {
+
+               /*
+                * FIXME: handle filter; for now we just receive the filter's
+                * bytecode along with the filter expression which are sent by
+                * liblttng-ctl and discard them.
+                *
+                * This fixes an issue where the client may block while sending
+                * the filter payload and encounter an error because the session
+                * daemon closes the socket without ever handling this data.
+                */
+               size_t count = cmd_ctx->lsm->u.disable.expression_len +
+                       cmd_ctx->lsm->u.disable.bytecode_len;
+
+               if (count) {
+                       char data[LTTNG_FILTER_MAX_LEN];
+
+                       DBG("Discarding disable event command payload of size %zu", count);
+                       while (count) {
+                               ret = lttcomm_recv_unix_sock(sock, data,
+                                       count > sizeof(data) ? sizeof(data) : count);
+                               if (ret < 0) {
+                                       goto error;
+                               }
+
+                               count -= (size_t) ret;
+                       }
+               }
                /* FIXME: passing packed structure to non-packed pointer */
-               /* TODO: handle filter */
                ret = cmd_disable_event(cmd_ctx->session, cmd_ctx->lsm->domain.type,
                                cmd_ctx->lsm->u.disable.channel_name,
                                &cmd_ctx->lsm->u.disable.event);
@@ -3146,8 +3369,25 @@ skip_domain:
        }
        case LTTNG_ENABLE_CHANNEL:
        {
+               cmd_ctx->lsm->u.channel.chan.attr.extended.ptr =
+                               (struct lttng_channel_extended *) &cmd_ctx->lsm->u.channel.extended;
                ret = cmd_enable_channel(cmd_ctx->session, &cmd_ctx->lsm->domain,
-                               &cmd_ctx->lsm->u.channel.chan, kernel_poll_pipe[1]);
+                               &cmd_ctx->lsm->u.channel.chan,
+                               kernel_poll_pipe[1]);
+               break;
+       }
+       case LTTNG_TRACK_PID:
+       {
+               ret = cmd_track_pid(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type,
+                               cmd_ctx->lsm->u.pid_tracker.pid);
+               break;
+       }
+       case LTTNG_UNTRACK_PID:
+       {
+               ret = cmd_untrack_pid(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type,
+                               cmd_ctx->lsm->u.pid_tracker.pid);
                break;
        }
        case LTTNG_ENABLE_EVENT:
@@ -3278,18 +3518,14 @@ skip_domain:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_event) * nb_events);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, events,
+                       sizeof(struct lttng_event) * nb_events);
+               free(events);
+
                if (ret < 0) {
-                       free(events);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, events,
-                               sizeof(struct lttng_event) * nb_events);
-
-               free(events);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3312,19 +3548,14 @@ skip_domain:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx,
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, fields,
                                sizeof(struct lttng_event_field) * nb_fields);
+               free(fields);
+
                if (ret < 0) {
-                       free(fields);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, fields,
-                               sizeof(struct lttng_event_field) * nb_fields);
-
-               free(fields);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3344,17 +3575,41 @@ skip_domain:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_event) * nb_events);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, events,
+                       sizeof(struct lttng_event) * nb_events);
+               free(events);
+
                if (ret < 0) {
-                       free(events);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, events,
-                               sizeof(struct lttng_event) * nb_events);
+               ret = LTTNG_OK;
+               break;
+       }
+       case LTTNG_LIST_TRACKER_PIDS:
+       {
+               int32_t *pids = NULL;
+               ssize_t nr_pids;
 
-               free(events);
+               nr_pids = cmd_list_tracker_pids(cmd_ctx->session,
+                               cmd_ctx->lsm->domain.type, &pids);
+               if (nr_pids < 0) {
+                       /* Return value is a negative lttng_error_code. */
+                       ret = -nr_pids;
+                       goto error;
+               }
+
+               /*
+                * Setup lttng message with payload size set to the event list size in
+                * bytes and then copy list into the llm payload.
+                */
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, pids,
+                       sizeof(int32_t) * nr_pids);
+               free(pids);
+
+               if (ret < 0) {
+                       goto setup_error;
+               }
 
                ret = LTTNG_OK;
                break;
@@ -3389,31 +3644,12 @@ skip_domain:
                        goto error;
                }
 
-               ret = cmd_set_consumer_uri(cmd_ctx->lsm->domain.type, cmd_ctx->session,
-                               nb_uri, uris);
+               ret = cmd_set_consumer_uri(cmd_ctx->session, nb_uri, uris);
+               free(uris);
                if (ret != LTTNG_OK) {
-                       free(uris);
                        goto error;
                }
 
-               /*
-                * XXX: 0 means that this URI should be applied on the session. Should
-                * be a DOMAIN enuam.
-                */
-               if (cmd_ctx->lsm->domain.type == 0) {
-                       /* Add the URI for the UST session if a consumer is present. */
-                       if (cmd_ctx->session->ust_session &&
-                                       cmd_ctx->session->ust_session->consumer) {
-                               ret = cmd_set_consumer_uri(LTTNG_DOMAIN_UST, cmd_ctx->session,
-                                               nb_uri, uris);
-                       } else if (cmd_ctx->session->kernel_session &&
-                                       cmd_ctx->session->kernel_session->consumer) {
-                               ret = cmd_set_consumer_uri(LTTNG_DOMAIN_KERNEL,
-                                               cmd_ctx->session, nb_uri, uris);
-                       }
-               }
-
-               free(uris);
 
                break;
        }
@@ -3488,46 +3724,38 @@ skip_domain:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, nb_dom * sizeof(struct lttng_domain));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, domains,
+                       nb_dom * sizeof(struct lttng_domain));
+               free(domains);
+
                if (ret < 0) {
-                       free(domains);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, domains,
-                               nb_dom * sizeof(struct lttng_domain));
-
-               free(domains);
-
                ret = LTTNG_OK;
                break;
        }
        case LTTNG_LIST_CHANNELS:
        {
-               int nb_chan;
+               ssize_t payload_size;
                struct lttng_channel *channels = NULL;
 
-               nb_chan = cmd_list_channels(cmd_ctx->lsm->domain.type,
+               payload_size = cmd_list_channels(cmd_ctx->lsm->domain.type,
                                cmd_ctx->session, &channels);
-               if (nb_chan < 0) {
+               if (payload_size < 0) {
                        /* Return value is a negative lttng_error_code. */
-                       ret = -nb_chan;
+                       ret = -payload_size;
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, nb_chan * sizeof(struct lttng_channel));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, channels,
+                       payload_size);
+               free(channels);
+
                if (ret < 0) {
-                       free(channels);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, channels,
-                               nb_chan * sizeof(struct lttng_channel));
-
-               free(channels);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3535,61 +3763,68 @@ skip_domain:
        {
                ssize_t nb_event;
                struct lttng_event *events = NULL;
+               struct lttcomm_event_command_header cmd_header;
+               size_t total_size;
+
+               memset(&cmd_header, 0, sizeof(cmd_header));
+               /* Extended infos are included at the end of events */
+               nb_event = cmd_list_events(cmd_ctx->lsm->domain.type,
+                       cmd_ctx->session, cmd_ctx->lsm->u.list.channel_name,
+                       &events, &total_size);
 
-               nb_event = cmd_list_events(cmd_ctx->lsm->domain.type, cmd_ctx->session,
-                               cmd_ctx->lsm->u.list.channel_name, &events);
                if (nb_event < 0) {
                        /* Return value is a negative lttng_error_code. */
                        ret = -nb_event;
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, nb_event * sizeof(struct lttng_event));
+               cmd_header.nb_events = nb_event;
+               ret = setup_lttng_msg(cmd_ctx, events, total_size,
+                       &cmd_header, sizeof(cmd_header));
+               free(events);
+
                if (ret < 0) {
-                       free(events);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, events,
-                               nb_event * sizeof(struct lttng_event));
-
-               free(events);
-
                ret = LTTNG_OK;
                break;
        }
        case LTTNG_LIST_SESSIONS:
        {
                unsigned int nr_sessions;
+               void *sessions_payload;
+               size_t payload_len;
 
                session_lock_list();
                nr_sessions = lttng_sessions_count(
                                LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
                                LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds));
+               payload_len = sizeof(struct lttng_session) * nr_sessions;
+               sessions_payload = zmalloc(payload_len);
 
-               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_session) * nr_sessions);
-               if (ret < 0) {
+               if (!sessions_payload) {
                        session_unlock_list();
+                       ret = -ENOMEM;
                        goto setup_error;
                }
 
-               /* Filled the session array */
-               cmd_list_lttng_sessions((struct lttng_session *)(cmd_ctx->llm->payload),
+               cmd_list_lttng_sessions(sessions_payload,
                        LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
                        LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds));
-
                session_unlock_list();
 
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, sessions_payload,
+                       payload_len);
+               free(sessions_payload);
+
+               if (ret < 0) {
+                       goto setup_error;
+               }
+
                ret = LTTNG_OK;
                break;
        }
-       case LTTNG_CALIBRATE:
-       {
-               ret = cmd_calibrate(cmd_ctx->lsm->domain.type,
-                               &cmd_ctx->lsm->u.calibrate);
-               break;
-       }
        case LTTNG_REGISTER_CONSUMER:
        {
                struct consumer_data *cdata;
@@ -3609,7 +3844,44 @@ skip_domain:
        }
        case LTTNG_DATA_PENDING:
        {
-               ret = cmd_data_pending(cmd_ctx->session);
+               int pending_ret;
+               uint8_t pending_ret_byte;
+
+               pending_ret = cmd_data_pending(cmd_ctx->session);
+
+               /*
+                * FIXME
+                *
+                * This function may returns 0 or 1 to indicate whether or not
+                * there is data pending. In case of error, it should return an
+                * LTTNG_ERR code. However, some code paths may still return
+                * a nondescript error code, which we handle by returning an
+                * "unknown" error.
+                */
+               if (pending_ret == 0 || pending_ret == 1) {
+                       /*
+                        * ret will be set to LTTNG_OK at the end of
+                        * this function.
+                        */
+               } else if (pending_ret < 0) {
+                       ret = LTTNG_ERR_UNK;
+                       goto setup_error;
+               } else {
+                       ret = pending_ret;
+                       goto setup_error;
+               }
+
+               pending_ret_byte = (uint8_t) pending_ret;
+
+               /* 1 byte to return whether or not data is pending */
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx,
+                       &pending_ret_byte, 1);
+
+               if (ret < 0) {
+                       goto setup_error;
+               }
+
+               ret = LTTNG_OK;
                break;
        }
        case LTTNG_SNAPSHOT_ADD_OUTPUT:
@@ -3622,13 +3894,13 @@ skip_domain:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, sizeof(reply));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, &reply,
+                       sizeof(reply));
                if (ret < 0) {
                        goto setup_error;
                }
 
                /* Copy output list into message payload */
-               memcpy(cmd_ctx->llm->payload, &reply, sizeof(reply));
                ret = LTTNG_OK;
                break;
        }
@@ -3649,20 +3921,15 @@ skip_domain:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx,
+               assert((nb_output > 0 && outputs) || nb_output == 0);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, outputs,
                                nb_output * sizeof(struct lttng_snapshot_output));
+               free(outputs);
+
                if (ret < 0) {
-                       free(outputs);
                        goto setup_error;
                }
 
-               if (outputs) {
-                       /* Copy output list into message payload */
-                       memcpy(cmd_ctx->llm->payload, outputs,
-                                       nb_output * sizeof(struct lttng_snapshot_output));
-                       free(outputs);
-               }
-
                ret = LTTNG_OK;
                break;
        }
@@ -3757,6 +4024,34 @@ skip_domain:
                        &cmd_ctx->creds);
                break;
        }
+       case LTTNG_SET_SESSION_SHM_PATH:
+       {
+               ret = cmd_set_session_shm_path(cmd_ctx->session,
+                               cmd_ctx->lsm->u.set_shm_path.shm_path);
+               break;
+       }
+       case LTTNG_REGENERATE_METADATA:
+       {
+               ret = cmd_regenerate_metadata(cmd_ctx->session);
+               break;
+       }
+       case LTTNG_REGENERATE_STATEDUMP:
+       {
+               ret = cmd_regenerate_statedump(cmd_ctx->session);
+               break;
+       }
+       case LTTNG_REGISTER_TRIGGER:
+       {
+               ret = cmd_register_trigger(cmd_ctx, sock,
+                               notification_thread_handle);
+               break;
+       }
+       case LTTNG_UNREGISTER_TRIGGER:
+       {
+               ret = cmd_unregister_trigger(cmd_ctx, sock,
+                               notification_thread_handle);
+               break;
+       }
        default:
                ret = LTTNG_ERR_UND;
                break;
@@ -3765,7 +4060,7 @@ skip_domain:
 error:
        if (cmd_ctx->llm == NULL) {
                DBG("Missing llm structure. Allocating one.");
-               if (setup_lttng_msg(cmd_ctx, 0) < 0) {
+               if (setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0) < 0) {
                        goto setup_error;
                }
        }
@@ -3779,6 +4074,7 @@ setup_error:
                session_unlock_list();
        }
 init_setup_error:
+       assert(!rcu_read_ongoing());
        return ret;
 }
 
@@ -3801,30 +4097,27 @@ static void *thread_manage_health(void *data)
        lttng_poll_init(&events);
 
        /* Create unix socket */
-       sock = lttcomm_create_unix_sock(health_unix_sock_path);
+       sock = lttcomm_create_unix_sock(config.health_unix_sock_path.value);
        if (sock < 0) {
                ERR("Unable to create health check Unix socket");
-               ret = -1;
                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 = chown(config.health_unix_sock_path.value, 0,
+                               utils_get_group_id(config.tracing_group_name.value));
                if (ret < 0) {
-                       ERR("Unable to set group on %s", health_unix_sock_path);
+                       ERR("Unable to set group on %s", config.health_unix_sock_path.value);
                        PERROR("chown");
-                       ret = -1;
                        goto error;
                }
 
-               ret = chmod(health_unix_sock_path,
+               ret = chmod(config.health_unix_sock_path.value,
                                S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
                if (ret < 0) {
-                       ERR("Unable to set permissions on %s", health_unix_sock_path);
+                       ERR("Unable to set permissions on %s", config.health_unix_sock_path.value);
                        PERROR("chmod");
-                       ret = -1;
                        goto error;
                }
        }
@@ -3880,6 +4173,11 @@ restart:
                        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) {
@@ -3889,9 +4187,14 @@ restart:
 
                        /* Event on the registration socket */
                        if (pollfd == sock) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               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;
                                }
                        }
                }
@@ -3915,7 +4218,6 @@ restart:
                        if (ret) {
                                PERROR("close");
                        }
-                       new_sock = -1;
                        continue;
                }
 
@@ -3944,7 +4246,6 @@ restart:
                if (ret) {
                        PERROR("close");
                }
-               new_sock = -1;
        }
 
 exit:
@@ -3953,7 +4254,7 @@ error:
                ERR("Health error occurred in %s", __func__);
        }
        DBG("Health check thread dying");
-       unlink(health_unix_sock_path);
+       unlink(config.health_unix_sock_path.value);
        if (sock >= 0) {
                ret = close(sock);
                if (ret) {
@@ -3962,7 +4263,7 @@ error:
        }
 
        lttng_poll_clean(&events);
-
+       stop_threads();
        rcu_unregister_thread();
        return NULL;
 }
@@ -4052,6 +4353,11 @@ static void *thread_manage_clients(void *data)
 
                        health_code_update();
 
+                       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) {
@@ -4061,9 +4367,14 @@ static void *thread_manage_clients(void *data)
 
                        /* Event on the registration socket */
                        if (pollfd == client_sock) {
-                               if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+                               if (revents & LPOLLIN) {
+                                       continue;
+                               } else if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
                                        ERR("Client socket poll error");
                                        goto error;
+                               } else {
+                                       ERR("Unexpected poll events %u for sock %d", revents, pollfd);
+                                       goto error;
                                }
                        }
                }
@@ -4160,9 +4471,10 @@ static void *thread_manage_clients(void *data)
 
                health_code_update();
 
-               DBG("Sending response (size: %d, retcode: %s)",
+               DBG("Sending response (size: %d, retcode: %s (%d))",
                                cmd_ctx->lttng_msg_size,
-                               lttng_strerror(-cmd_ctx->llm->ret_code));
+                               lttng_strerror(-cmd_ctx->llm->ret_code),
+                               cmd_ctx->llm->ret_code);
                ret = send_unix_sock(sock, cmd_ctx->llm, cmd_ctx->lttng_msg_size);
                if (ret < 0) {
                        ERR("Failed to send data back to client");
@@ -4194,7 +4506,7 @@ 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) {
@@ -4212,44 +4524,34 @@ error_create_poll:
        DBG("Client thread dying");
 
        rcu_unregister_thread();
+
+       /*
+        * Since we are creating the consumer threads, we own them, so we need
+        * to join them before our thread exits.
+        */
+       ret = join_consumer_thread(&kconsumer_data);
+       if (ret) {
+               errno = ret;
+               PERROR("join_consumer");
+       }
+
+       ret = join_consumer_thread(&ustconsumer32_data);
+       if (ret) {
+               errno = ret;
+               PERROR("join_consumer ust32");
+       }
+
+       ret = join_consumer_thread(&ustconsumer64_data);
+       if (ret) {
+               errno = ret;
+               PERROR("join_consumer ust64");
+       }
        return NULL;
 }
 
-
-/*
- * usage function on stderr
- */
-static void usage(void)
+static int string_match(const char *str1, const char *str2)
 {
-       fprintf(stderr, "Usage: %s OPTIONS\n\nOptions:\n", progname);
-       fprintf(stderr, "  -h, --help                         Display this usage.\n");
-       fprintf(stderr, "  -c, --client-sock PATH             Specify path for the client unix socket\n");
-       fprintf(stderr, "  -a, --apps-sock PATH               Specify path for apps unix socket\n");
-       fprintf(stderr, "      --kconsumerd-err-sock PATH     Specify path for the kernel consumer error socket\n");
-       fprintf(stderr, "      --kconsumerd-cmd-sock PATH     Specify path for the kernel consumer command socket\n");
-       fprintf(stderr, "      --ustconsumerd32-err-sock PATH Specify path for the 32-bit UST consumer error socket\n");
-       fprintf(stderr, "      --ustconsumerd64-err-sock PATH Specify path for the 64-bit UST consumer error socket\n");
-       fprintf(stderr, "      --ustconsumerd32-cmd-sock PATH Specify path for the 32-bit UST consumer command socket\n");
-       fprintf(stderr, "      --ustconsumerd64-cmd-sock PATH Specify path for the 64-bit UST consumer command socket\n");
-       fprintf(stderr, "      --consumerd32-path PATH     Specify path for the 32-bit UST consumer daemon binary\n");
-       fprintf(stderr, "      --consumerd32-libdir PATH   Specify path for the 32-bit UST consumer daemon libraries\n");
-       fprintf(stderr, "      --consumerd64-path PATH     Specify path for the 64-bit UST consumer daemon binary\n");
-       fprintf(stderr, "      --consumerd64-libdir PATH   Specify path for the 64-bit UST consumer daemon libraries\n");
-       fprintf(stderr, "  -d, --daemonize                    Start as a daemon.\n");
-       fprintf(stderr, "  -b, --background                   Start as a daemon, keeping console open.\n");
-       fprintf(stderr, "  -g, --group NAME                   Specify the tracing group name. (default: tracing)\n");
-       fprintf(stderr, "  -V, --version                      Show version number.\n");
-       fprintf(stderr, "  -S, --sig-parent                   Send SIGUSR1 to parent pid to notify readiness.\n");
-       fprintf(stderr, "  -q, --quiet                        No output at all.\n");
-       fprintf(stderr, "  -v, --verbose                      Verbose mode. Activate DBG() macro.\n");
-       fprintf(stderr, "  -p, --pidfile FILE                 Write a pid to FILE name overriding the default value.\n");
-       fprintf(stderr, "      --verbose-consumer             Verbose mode for consumer. Activate DBG() macro.\n");
-       fprintf(stderr, "      --no-kernel                    Disable kernel tracer\n");
-       fprintf(stderr, "      --agent-tcp-port               Agent registration TCP port\n");
-       fprintf(stderr, "  -f  --config PATH                  Load daemon configuration file\n");
-       fprintf(stderr, "  -l  --load PATH                    Load session configuration\n");
-       fprintf(stderr, "      --kmod-probes                  Specify kernel module probes to load\n");
-       fprintf(stderr, "      --extra-kmod-probes            Specify extra kernel module probes to load\n");
+       return (str1 && str2) && !strcmp(str1, str2);
 }
 
 /*
@@ -4262,203 +4564,341 @@ static int set_option(int opt, const char *arg, const char *optname)
 {
        int ret = 0;
 
-       if (arg && arg[0] == '\0') {
-               /*
-                * This only happens if the value is read from daemon config
-                * file. This means the option requires an argument and the
-                * configuration file contains a line such as:
-                * my_option =
-                */
-               ret = -EINVAL;
-               goto end;
-       }
-
-       switch (opt) {
-       case 0:
-               fprintf(stderr, "option %s", optname);
-               if (arg) {
-                       fprintf(stderr, " with arg %s\n", arg);
+       if (string_match(optname, "client-sock") || opt == 'c') {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               break;
-       case 'c':
-               snprintf(client_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'a':
-               snprintf(apps_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'd':
-               opt_daemon = 1;
-               break;
-       case 'b':
-               opt_background = 1;
-               break;
-       case 'g':
-               /*
-                * 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 (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-c, --client-sock");
+               } else {
+                       config_string_set(&config.client_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.client_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               tracing_group_name = strdup(arg);
-               if (!tracing_group_name) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+       } else if (string_match(optname, "apps-sock") || opt == 'a') {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               tracing_group_name_override = 1;
-               break;
-       case 'h':
-               usage();
-               exit(EXIT_FAILURE);
-       case 'V':
-               fprintf(stdout, "%s\n", VERSION);
-               exit(EXIT_SUCCESS);
-       case 'S':
-               opt_sig_parent = 1;
-               break;
-       case 'E':
-               snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'C':
-               snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'F':
-               snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'D':
-               snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'H':
-               snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'G':
-               snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX, "%s", arg);
-               break;
-       case 'N':
-               opt_no_kernel = 1;
-               break;
-       case 'q':
-               lttng_opt_quiet = 1;
-               break;
-       case 'v':
-               /* Verbose level can increase using multiple -v */
-               if (arg) {
-                       /* Value obtained from config file */
-                       lttng_opt_verbose = config_parse_value(arg);
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-a, --apps-sock");
                } else {
-                       /* -v used on command line */
-                       lttng_opt_verbose++;
+                       config_string_set(&config.apps_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.apps_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               /* Clamp value to [0, 3] */
-               lttng_opt_verbose = lttng_opt_verbose < 0 ? 0 :
-                       (lttng_opt_verbose <= 3 ? lttng_opt_verbose : 3);
-               break;
-       case 'Z':
-               if (arg) {
-                       opt_verbose_consumer = config_parse_value(arg);
+       } else if (string_match(optname, "daemonize") || opt == 'd') {
+               config.daemonize = true;
+       } else if (string_match(optname, "background") || opt == 'b') {
+               config.background = true;
+       } else if (string_match(optname, "group") || opt == 'g') {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-g, --group");
                } else {
-                       opt_verbose_consumer += 1;
+                       config_string_set(&config.tracing_group_name,
+                                       strdup(arg));
+                       if (!config.tracing_group_name.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               break;
-       case 'u':
-               if (consumerd32_bin_override) {
-                       free((void *) consumerd32_bin);
+       } else if (string_match(optname, "help") || opt == 'h') {
+               ret = utils_show_help(8, "lttng-sessiond", help_msg);
+               if (ret) {
+                       ERR("Cannot show --help for `lttng-sessiond`");
+                       perror("exec");
                }
-               consumerd32_bin = strdup(arg);
-               if (!consumerd32_bin) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+               exit(ret ? EXIT_FAILURE : EXIT_SUCCESS);
+       } else if (string_match(optname, "version") || opt == 'V') {
+               fprintf(stdout, "%s\n", VERSION);
+               exit(EXIT_SUCCESS);
+       } else if (string_match(optname, "sig-parent") || opt == 'S') {
+               config.sig_parent = true;
+       } else if (string_match(optname, "kconsumerd-err-sock")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               consumerd32_bin_override = 1;
-               break;
-       case 'U':
-               if (consumerd32_libdir_override) {
-                       free((void *) consumerd32_libdir);
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--kconsumerd-err-sock");
+               } else {
+                       config_string_set(&config.kconsumerd_err_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.kconsumerd_err_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               consumerd32_libdir = strdup(arg);
-               if (!consumerd32_libdir) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+       } else if (string_match(optname, "kconsumerd-cmd-sock")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               consumerd32_libdir_override = 1;
-               break;
-       case 't':
-               if (consumerd64_bin_override) {
-                       free((void *) consumerd64_bin);
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--kconsumerd-cmd-sock");
+               } else {
+                       config_string_set(&config.kconsumerd_cmd_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.kconsumerd_cmd_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               consumerd64_bin = strdup(arg);
-               if (!consumerd64_bin) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+       } else if (string_match(optname, "ustconsumerd64-err-sock")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               consumerd64_bin_override = 1;
-               break;
-       case 'T':
-               if (consumerd64_libdir_override) {
-                       free((void *) consumerd64_libdir);
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd64-err-sock");
+               } else {
+                       config_string_set(&config.consumerd64_err_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.consumerd64_err_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               consumerd64_libdir = strdup(arg);
-               if (!consumerd64_libdir) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+       } else if (string_match(optname, "ustconsumerd64-cmd-sock")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               consumerd64_libdir_override = 1;
-               break;
-       case 'p':
-               free(opt_pidfile);
-               opt_pidfile = strdup(arg);
-               if (!opt_pidfile) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd64-cmd-sock");
+               } else {
+                       config_string_set(&config.consumerd64_cmd_unix_sock_path,
+                                       strdup(arg));
+                       if (!config.consumerd64_cmd_unix_sock_path.value) {
+                               ret = -ENOMEM;
+                               PERROR("strdup");
+                       }
                }
-               break;
-       case 'J': /* Agent TCP port. */
-       {
-               unsigned long v;
+       } else if (string_match(optname, "ustconsumerd32-err-sock")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd32-err-sock");
+               } else {
+                       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') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--ustconsumerd32-cmd-sock");
+               } else {
+                       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")) {
+               config.no_kernel = true;
+       } else if (string_match(optname, "quiet") || opt == 'q') {
+               lttng_opt_quiet = true;
+       } else if (string_match(optname, "verbose") || opt == 'v') {
+               /* Verbose level can increase using multiple -v */
+               if (arg) {
+                       /* Value obtained from config file */
+                       config.verbose = config_parse_value(arg);
+               } else {
+                       /* -v used on command line */
+                       config.verbose++;
+               }
+               /* Clamp value to [0, 3] */
+               config.verbose = config.verbose < 0 ? 0 :
+                       (config.verbose <= 3 ? config.verbose : 3);
+       } else if (string_match(optname, "verbose-consumer")) {
+               if (arg) {
+                       config.verbose_consumer = config_parse_value(arg);
+               } else {
+                       config.verbose_consumer++;
+               }
+       } else if (string_match(optname, "consumerd32-path")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd32-path");
+               } else {
+                       config_string_set(&config.consumerd32_bin_path,
+                                       strdup(arg));
+                       if (!config.consumerd32_bin_path.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "consumerd32-libdir")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd32-libdir");
+               } else {
+                       config_string_set(&config.consumerd32_lib_dir,
+                                       strdup(arg));
+                       if (!config.consumerd32_lib_dir.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "consumerd64-path")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd64-path");
+               } else {
+                       config_string_set(&config.consumerd64_bin_path,
+                                       strdup(arg));
+                       if (!config.consumerd64_bin_path.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "consumerd64-libdir")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--consumerd64-libdir");
+               } else {
+                       config_string_set(&config.consumerd64_lib_dir,
+                                       strdup(arg));
+                       if (!config.consumerd64_lib_dir.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "pidfile") || opt == 'p') {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-p, --pidfile");
+               } else {
+                       config_string_set(&config.pid_file_path, strdup(arg));
+                       if (!config.pid_file_path.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "agent-tcp-port")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--agent-tcp-port");
+               } else {
+                       unsigned long v;
 
-               errno = 0;
-               v = strtoul(arg, NULL, 0);
-               if (errno != 0 || !isdigit(arg[0])) {
-                       ERR("Wrong value in --agent-tcp-port parameter: %s", arg);
-                       return -1;
+                       errno = 0;
+                       v = strtoul(arg, NULL, 0);
+                       if (errno != 0 || !isdigit(arg[0])) {
+                               ERR("Wrong value in --agent-tcp-port parameter: %s", arg);
+                               return -1;
+                       }
+                       if (v == 0 || v >= 65535) {
+                               ERR("Port overflow in --agent-tcp-port parameter: %s", arg);
+                               return -1;
+                       }
+                       config.agent_tcp_port = (uint32_t) v;
+                       DBG3("Agent TCP port set to non default: %u", config.agent_tcp_port);
                }
-               if (v == 0 || v >= 65535) {
-                       ERR("Port overflow in --agent-tcp-port parameter: %s", arg);
-                       return -1;
+       } else if (string_match(optname, "load") || opt == 'l') {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               agent_tcp_port = (uint32_t) v;
-               DBG3("Agent TCP port set to non default: %u", agent_tcp_port);
-               break;
-       }
-       case 'l':
-               free(opt_load_session_path);
-               opt_load_session_path = strdup(arg);
-               if (!opt_load_session_path) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-l, --load");
+               } else {
+                       config_string_set(&config.load_session_path, strdup(arg));
+                       if (!config.load_session_path.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
                }
-               break;
-       case 'P': /* probe modules list */
-               free(kmod_probes_list);
-               kmod_probes_list = strdup(arg);
-               if (!kmod_probes_list) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+       } else if (string_match(optname, "kmod-probes")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
                }
-               break;
-       case 'e':
-               free(kmod_extra_probes_list);
-               kmod_extra_probes_list = strdup(arg);
-               if (!kmod_extra_probes_list) {
-                       perror("strdup");
-                       ret = -ENOMEM;
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--kmod-probes");
+               } else {
+                       config_string_set(&config.kmod_probes_list, strdup(arg));
+                       if (!config.kmod_probes_list.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
                }
-               break;
-       case 'f':
-               /* This is handled in set_options() thus silent break. */
-               break;
-       default:
+       } else if (string_match(optname, "extra-kmod-probes")) {
+               if (!arg || *arg == '\0') {
+                       ret = -EINVAL;
+                       goto end;
+               }
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "--extra-kmod-probes");
+               } else {
+                       config_string_set(&config.kmod_extra_probes_list,
+                                       strdup(arg));
+                       if (!config.kmod_extra_probes_list.value) {
+                               PERROR("strdup");
+                               ret = -ENOMEM;
+                       }
+               }
+       } else if (string_match(optname, "config") || opt == 'f') {
+               /* This is handled in set_options() thus silent skip. */
+               goto end;
+       } else {
                /* Unknown option or other error.
                 * Error is printed by getopt, just return */
                ret = -1;
@@ -4486,7 +4926,7 @@ end:
 
 /*
  * config_entry_handler_cb used to handle options read from a config file.
- * See config_entry_handler_cb comment in common/config/config.h for the
+ * See config_entry_handler_cb comment in common/config/session-config.h for the
  * return value conventions.
  */
 static int config_entry_handler(const struct config_entry *entry, void *unused)
@@ -4568,9 +5008,14 @@ static int set_options(int argc, char **argv)
                        continue;
                }
 
-               config_path = utils_expand_path(optarg);
-               if (!config_path) {
-                       ERR("Failed to resolve path: %s", optarg);
+               if (lttng_is_setuid_setgid()) {
+                       WARN("Getting '%s' argument from setuid/setgid binary refused for security reasons.",
+                               "-f, --config");
+               } else {
+                       config_path = utils_expand_path(optarg);
+                       if (!config_path) {
+                               ERR("Failed to resolve path: %s", optarg);
+                       }
                }
        }
 
@@ -4588,12 +5033,24 @@ static int set_options(int argc, char **argv)
        optopt = orig_optopt;
        optind = orig_optind;
        while (1) {
-               c = getopt_long(argc, argv, optstring, long_options, &option_index);
+               option_index = -1;
+               /*
+                * getopt_long() will not set option_index if it encounters a
+                * short option.
+                */
+               c = getopt_long(argc, argv, optstring, long_options,
+                               &option_index);
                if (c == -1) {
                        break;
                }
 
-               ret = set_option(c, optarg, long_options[option_index].name);
+               /*
+                * Pass NULL as the long option name if popt left the index
+                * unset.
+                */
+               ret = set_option(c, optarg,
+                               option_index < 0 ? NULL :
+                               long_options[option_index].name);
                if (ret < 0) {
                        break;
                }
@@ -4617,9 +5074,9 @@ 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;
        }
@@ -4633,17 +5090,17 @@ 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;
        }
@@ -4657,10 +5114,10 @@ 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;
        }
@@ -4698,7 +5155,7 @@ 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);
@@ -4719,9 +5176,9 @@ 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");
        }
 
@@ -4754,16 +5211,16 @@ 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;
@@ -4775,44 +5232,41 @@ 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);
 
        ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP);
-       if (ret < 0) {
-               if (errno != EEXIST) {
-                       PERROR("mkdir");
-                       ERR("Failed to create %s", path);
-                       goto error;
-               }
-               ret = -1;
+       if (ret < 0 && errno != EEXIST) {
+               PERROR("mkdir");
+               ERR("Failed to create %s", path);
+               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");
@@ -4820,7 +5274,7 @@ 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) {
@@ -4861,9 +5315,6 @@ error:
 static void sighandler(int sig)
 {
        switch (sig) {
-       case SIGPIPE:
-               DBG("SIGPIPE caught");
-               return;
        case SIGINT:
                DBG("SIGINT caught");
                stop_threads();
@@ -4895,9 +5346,10 @@ static int set_signal_handler(void)
                return ret;
        }
 
-       sa.sa_handler = sighandler;
        sa.sa_mask = sigset;
        sa.sa_flags = 0;
+
+       sa.sa_handler = sighandler;
        if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
                PERROR("sigaction");
                return ret;
@@ -4908,12 +5360,13 @@ static int set_signal_handler(void)
                return ret;
        }
 
-       if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
+       if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
                PERROR("sigaction");
                return ret;
        }
 
-       if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
+       sa.sa_handler = SIG_IGN;
+       if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
                PERROR("sigaction");
                return ret;
        }
@@ -4925,14 +5378,14 @@ static int set_signal_handler(void)
 
 /*
  * Set open files limit to unlimited. This daemon can open a large number of
- * file descriptors in order to consumer multiple kernel traces.
+ * file descriptors in order to consume multiple kernel traces.
  */
 static void set_ulimit(void)
 {
        int ret;
        struct rlimit lim;
 
-       /* The kernel does not allowed an infinite limit for open files */
+       /* The kernel does not allow an infinite limit for open files */
        lim.rlim_cur = 65535;
        lim.rlim_max = 65535;
 
@@ -4942,36 +5395,9 @@ static void set_ulimit(void)
        }
 }
 
-/*
- * Write pidfile using the rundir and opt_pidfile.
- */
-static void write_pidfile(void)
+static int write_pidfile(void)
 {
-       int ret;
-       char pidfile_path[PATH_MAX];
-
-       assert(rundir);
-
-       if (opt_pidfile) {
-               strncpy(pidfile_path, opt_pidfile, sizeof(pidfile_path));
-       } 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. Return value is of no importance. The
-        * execution will continue even though we are not able to write the file.
-        */
-       (void) utils_create_pid_file(getpid(), pidfile_path);
-
-error:
-       return;
+        return utils_create_pid_file(getpid(), config.pid_file_path.value);
 }
 
 /*
@@ -4979,74 +5405,45 @@ error:
  */
 static int create_lockfile(void)
 {
-       int ret;
-       char lockfile_path[PATH_MAX];
-
-       ret = generate_lock_file_path(lockfile_path, sizeof(lockfile_path));
-       if (ret < 0) {
-               goto error;
-       }
-
-       ret = utils_create_lock_file(lockfile_path);
-error:
-       return ret;
+        return utils_create_lock_file(config.lock_file_path.value);
 }
 
 /*
  * Write agent TCP port using the rundir.
  */
-static void write_agent_port(void)
+static int write_agent_port(void)
 {
-       int ret;
-       char path[PATH_MAX];
-
-       assert(rundir);
-
-       ret = snprintf(path, sizeof(path), "%s/"
-                       DEFAULT_LTTNG_SESSIOND_AGENTPORT_FILE, rundir);
-       if (ret < 0) {
-               PERROR("snprintf agent port path");
-               goto error;
-       }
-
-       /*
-        * Create TCP agent port file in rundir. Return value is of no importance.
-        * The execution will continue even though we are not able to write the
-        * file.
-        */
-       (void) utils_create_pid_file(agent_tcp_port, path);
-
-error:
-       return;
+       return utils_create_pid_file(config.agent_tcp_port,
+                       config.agent_port_file_path.value);
 }
 
-/*
- * Start the load session thread and dettach from it so the main thread can
- * continue. This does not return a value since whatever the outcome, the main
- * thread will continue.
- */
-static void start_load_session_thread(void)
+static int set_clock_plugin_env(void)
 {
-       int ret;
+       int ret = 0;
+       char *env_value = NULL;
 
-       /* Create session loading thread. */
-       ret = pthread_create(&load_session_thread, NULL, thread_load_session,
-                       load_info);
-       if (ret != 0) {
-               PERROR("pthread_create load_session_thread");
-               goto error_create;
+       if (!config.lttng_ust_clock_plugin.value) {
+               goto end;
        }
 
-       ret = pthread_detach(load_session_thread);
-       if (ret != 0) {
-               PERROR("pthread_detach load_session_thread");
+        ret = asprintf(&env_value, "LTTNG_UST_CLOCK_PLUGIN=%s",
+                       config.lttng_ust_clock_plugin.value);
+       if (ret < 0) {
+               PERROR("asprintf");
+               goto end;
        }
 
-       /* Everything went well so don't cleanup anything. */
+       ret = putenv(env_value);
+       if (ret) {
+               free(env_value);
+               PERROR("putenv of LTTNG_UST_CLOCK_PLUGIN");
+               goto end;
+       }
 
-error_create:
-       /* The cleanup() function will destroy the load_info data. */
-       return;
+       DBG("Updated LTTNG_UST_CLOCK_PLUGIN environment variable to \"%s\"",
+                       config.lttng_ust_clock_plugin.value);
+end:
+       return ret;
 }
 
 /*
@@ -5054,20 +5451,23 @@ error_create:
  */
 int main(int argc, char **argv)
 {
-       int ret = 0;
+       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;
 
        init_kernel_workarounds();
 
        rcu_register_thread();
 
-       if ((ret = set_signal_handler()) < 0) {
-               goto error;
+       if (set_signal_handler()) {
+               retval = -1;
+               goto exit_set_signal_handler;
        }
 
-       setup_consumerd_path();
-
        page_size = sysconf(_SC_PAGESIZE);
        if (page_size < 0) {
                PERROR("sysconf _SC_PAGESIZE");
@@ -5075,193 +5475,205 @@ int main(int argc, char **argv)
                WARN("Fallback page size to %ld", page_size);
        }
 
-       /* Parse arguments and load the daemon configuration file */
+       ret = sessiond_config_init(&config);
+       if (ret) {
+               retval = -1;
+               goto exit_set_signal_handler;
+       }
+
+       /*
+        * Parse arguments and load the daemon configuration file.
+        *
+        * We have an exit_options exit path to free memory reserved by
+        * set_options. This is needed because the rest of sessiond_cleanup()
+        * depends on ht_cleanup_thread, which depends on lttng_daemonize, which
+        * depends on set_options.
+        */
        progname = argv[0];
-       if ((ret = set_options(argc, argv)) < 0) {
-               goto error;
+       if (set_options(argc, argv)) {
+               retval = -1;
+               goto exit_options;
        }
 
+       /* Init config from environment variables. */
+       sessiond_config_apply_env_config(&config);
+
+       /*
+        * 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);
+
        /* 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) {
-                       goto error;
+                       retval = -1;
+                       goto exit_options;
                }
 
                /*
                 * 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.
+                * closed, in case we are called with more opened file
+                * descriptors than the standard ones.
                 */
                for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
                        (void) close(i);
                }
        }
 
+       if (run_as_create_worker(argv[0]) < 0) {
+               goto exit_create_run_as_worker_cleanup;
+       }
+
+       /*
+        * Starting from here, we can create threads. This needs to be after
+        * lttng_daemonize due to RCU.
+        */
+
+       /*
+        * Initialize the health check subsystem. This call should set the
+        * appropriate time values.
+        */
+       health_sessiond = health_app_create(NR_HEALTH_SESSIOND_TYPES);
+       if (!health_sessiond) {
+               PERROR("health_app_create error");
+               retval = -1;
+               goto exit_health_sessiond_cleanup;
+       }
+
+       /* Create thread to clean up RCU hash tables */
+       if (init_ht_cleanup_thread(&ht_cleanup_thread)) {
+               retval = -1;
+               goto exit_ht_cleanup;
+       }
+
        /* Create thread quit pipe */
-       if ((ret = init_thread_quit_pipe()) < 0) {
-               goto error;
+       if (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) {
-                       ret = -ENOMEM;
-                       goto error;
-               }
-
                /* Create global run dir with root access */
-               ret = create_lttng_rundir(rundir);
-               if (ret < 0) {
-                       goto error;
-               }
-
-               if (strlen(apps_unix_sock_path) == 0) {
-                       snprintf(apps_unix_sock_path, PATH_MAX,
-                                       DEFAULT_GLOBAL_APPS_UNIX_SOCK);
-               }
-
-               if (strlen(client_unix_sock_path) == 0) {
-                       snprintf(client_unix_sock_path, PATH_MAX,
-                                       DEFAULT_GLOBAL_CLIENT_UNIX_SOCK);
-               }
-
-               /* Set global SHM for ust */
-               if (strlen(wait_shm_path) == 0) {
-                       snprintf(wait_shm_path, PATH_MAX,
-                                       DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH);
-               }
-
-               if (strlen(health_unix_sock_path) == 0) {
-                       snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
-                                       DEFAULT_GLOBAL_HEALTH_UNIX_SOCK);
-               }
-
-               /* Setup kernel consumerd path */
-               snprintf(kconsumer_data.err_unix_sock_path, PATH_MAX,
-                               DEFAULT_KCONSUMERD_ERR_SOCK_PATH, rundir);
-               snprintf(kconsumer_data.cmd_unix_sock_path, PATH_MAX,
-                               DEFAULT_KCONSUMERD_CMD_SOCK_PATH, rundir);
-
-               DBG2("Kernel consumer err path: %s",
-                               kconsumer_data.err_unix_sock_path);
-               DBG2("Kernel consumer cmd path: %s",
-                               kconsumer_data.cmd_unix_sock_path);
-       } else {
-               home_path = utils_get_home_dir();
-               if (home_path == NULL) {
-                       /* TODO: Add --socket PATH option */
-                       ERR("Can't get HOME directory for sockets creation.");
-                       ret = -EPERM;
-                       goto error;
-               }
-
-               /*
-                * Create rundir from home path. This will create something like
-                * $HOME/.lttng
-                */
-               ret = asprintf(&rundir, DEFAULT_LTTNG_HOME_RUNDIR, home_path);
-               if (ret < 0) {
-                       ret = -ENOMEM;
-                       goto error;
+               if (create_lttng_rundir()) {
+                       retval = -1;
+                       goto exit_init_data;
                }
 
-               ret = create_lttng_rundir(rundir);
-               if (ret < 0) {
-                       goto error;
+               kernel_channel_monitor_pipe = lttng_pipe_open(0);
+               if (!kernel_channel_monitor_pipe) {
+                       ERR("Failed to create kernel consumer channel monitor pipe");
+                       retval = -1;
+                       goto exit_init_data;
                }
-
-               if (strlen(apps_unix_sock_path) == 0) {
-                       snprintf(apps_unix_sock_path, PATH_MAX,
-                                       DEFAULT_HOME_APPS_UNIX_SOCK, home_path);
-               }
-
-               /* Set the cli tool unix socket path */
-               if (strlen(client_unix_sock_path) == 0) {
-                       snprintf(client_unix_sock_path, PATH_MAX,
-                                       DEFAULT_HOME_CLIENT_UNIX_SOCK, home_path);
-               }
-
-               /* Set global SHM for ust */
-               if (strlen(wait_shm_path) == 0) {
-                       snprintf(wait_shm_path, PATH_MAX,
-                                       DEFAULT_HOME_APPS_WAIT_SHM_PATH, getuid());
-               }
-
-               /* Set health check Unix path */
-               if (strlen(health_unix_sock_path) == 0) {
-                       snprintf(health_unix_sock_path, sizeof(health_unix_sock_path),
-                                       DEFAULT_HOME_HEALTH_UNIX_SOCK, home_path);
+               kconsumer_data.channel_monitor_pipe =
+                               lttng_pipe_release_writefd(
+                                       kernel_channel_monitor_pipe);
+               if (kconsumer_data.channel_monitor_pipe < 0) {
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
        lockfile_fd = create_lockfile();
        if (lockfile_fd < 0) {
-               goto error;
+               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 */
-       snprintf(ustconsumer32_data.err_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH, rundir);
-       snprintf(ustconsumer32_data.cmd_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD32_CMD_SOCK_PATH, rundir);
-
-       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);
-
-       /* 64 bits consumerd path setup */
-       snprintf(ustconsumer64_data.err_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD64_ERR_SOCK_PATH, rundir);
-       snprintf(ustconsumer64_data.cmd_unix_sock_path, PATH_MAX,
-                       DEFAULT_USTCONSUMERD64_CMD_SOCK_PATH, rundir);
-
-       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);
+       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");
+               retval = -1;
+               goto exit_init_data;
+       }
+       ustconsumer32_data.channel_monitor_pipe = lttng_pipe_release_writefd(
+                       ust32_channel_monitor_pipe);
+       if (ustconsumer32_data.channel_monitor_pipe < 0) {
+               retval = -1;
+               goto exit_init_data;
+       }
+
+       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");
+               retval = -1;
+               goto exit_init_data;
+       }
+       ustconsumer64_data.channel_monitor_pipe = lttng_pipe_release_writefd(
+                       ust64_channel_monitor_pipe);
+       if (ustconsumer64_data.channel_monitor_pipe < 0) {
+               retval = -1;
+               goto exit_init_data;
+       }
 
        /*
         * See if daemon already exist.
         */
-       if ((ret = check_existing_daemon()) < 0) {
+       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.
                 */
-               goto error;
+               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.
         */
-       ust_app_ht_alloc();
-
-       /* Initialize agent domain subsystem. */
-       if ((ret = agent_setup()) < 0) {
-               /* ENOMEM at this point. */
-               goto error;
+       if (ust_app_ht_alloc()) {
+               ERR("Failed to allocate UST app hash table");
+               retval = -1;
+               goto exit_init_data;
        }
 
-       /* After this point, we can safely call cleanup() with "goto exit" */
+       /*
+        * Initialize agent app hash table. We allocate the hash table here
+        * since cleanup() can get called after this point.
+        */
+       if (agent_app_ht_alloc()) {
+               ERR("Failed to allocate Agent app hash table");
+               retval = -1;
+               goto exit_init_data;
+       }
 
        /*
         * These actions must be executed as root. We do that *after* setting up
@@ -5270,19 +5682,20 @@ int main(int argc, char **argv)
         * kernel tracer.
         */
        if (is_root) {
-               ret = set_consumer_sockets(&kconsumer_data, rundir);
-               if (ret < 0) {
-                       goto exit;
+               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();
                                if (ret < 0) {
-                                       ERR("Unable to populate syscall table. Syscall tracing"
-                                                       " won't work for this session daemon.");
+                                       ERR("Unable to populate syscall table. "
+                                               "Syscall tracing won't work "
+                                               "for this session daemon.");
                                }
                        }
                }
@@ -5293,51 +5706,51 @@ int main(int argc, char **argv)
        /* init lttng_fd tracking must be done after set_ulimit. */
        lttng_fd_init();
 
-       ret = set_consumer_sockets(&ustconsumer64_data, rundir);
-       if (ret < 0) {
-               goto exit;
+       if (set_consumer_sockets(&ustconsumer64_data)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
-       ret = set_consumer_sockets(&ustconsumer32_data, rundir);
-       if (ret < 0) {
-               goto exit;
+       if (set_consumer_sockets(&ustconsumer32_data)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Setup the needed unix socket */
-       if ((ret = init_daemon_socket()) < 0) {
-               goto exit;
+       if (init_daemon_socket()) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Set credentials to socket */
-       if (is_root && ((ret = set_permissions(rundir)) < 0)) {
-               goto exit;
+       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 ((ret = utils_create_pipe_cloexec(kernel_poll_pipe)) < 0) {
-                       goto exit;
+       if (is_root && !config.no_kernel) {
+               if (utils_create_pipe_cloexec(kernel_poll_pipe)) {
+                       retval = -1;
+                       goto exit_init_data;
                }
        }
 
-       /* Setup the thread ht_cleanup communication pipe. */
-       if (utils_create_pipe_cloexec(ht_cleanup_pipe) < 0) {
-               goto exit;
-       }
-
        /* Setup the thread apps communication pipe. */
-       if ((ret = utils_create_pipe_cloexec(apps_cmd_pipe)) < 0) {
-               goto exit;
+       if (utils_create_pipe_cloexec(apps_cmd_pipe)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Setup the thread apps notify communication pipe. */
-       if (utils_create_pipe_cloexec(apps_cmd_notify_pipe) < 0) {
-               goto exit;
+       if (utils_create_pipe_cloexec(apps_cmd_notify_pipe)) {
+               retval = -1;
+               goto exit_init_data;
        }
 
        /* Initialize global buffer per UID and PID registry. */
@@ -5348,221 +5761,317 @@ int main(int argc, char **argv)
        cds_wfcq_init(&ust_cmd_queue.head, &ust_cmd_queue.tail);
 
        /*
-        * Get session list pointer. This pointer MUST NOT be free(). This list is
-        * statically declared in session.c
+        * 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();
 
-       /* Set up max poll set size */
-       lttng_poll_set_max_size();
-
        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;
        }
 
-       write_pidfile();
-       write_agent_port();
+       ret = write_pidfile();
+       if (ret) {
+               ERR("Error in write_pidfile");
+               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();
-       /* This is to get the TCP timeout value. */
+       /* Initialize TCP timeout values */
        lttcomm_inet_init();
 
        if (load_session_init_data(&load_info) < 0) {
-               goto exit;
+               retval = -1;
+               goto exit_init_data;
        }
-       load_info->path = opt_load_session_path;
+       load_info->path = config.load_session_path.value;
 
-       /*
-        * Initialize the health check subsystem. This call should set the
-        * appropriate time values.
-        */
-       health_sessiond = health_app_create(NR_HEALTH_SESSIOND_TYPES);
-       if (!health_sessiond) {
-               PERROR("health_app_create error");
-               goto exit_health_sessiond_cleanup;
+       /* 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");
+               retval = -1;
+               goto exit_health;
        }
 
-       /* Create thread to clean up RCU hash tables */
-       ret = pthread_create(&ht_cleanup_thread, NULL,
-                       thread_ht_cleanup, (void *) NULL);
-       if (ret != 0) {
-               PERROR("pthread_create ht_cleanup");
-               goto exit_ht_cleanup;
+       /* notification_thread_data acquires the pipes' read side. */
+       notification_thread_handle = notification_thread_handle_create(
+                       ust32_channel_monitor_pipe,
+                       ust64_channel_monitor_pipe,
+                       kernel_channel_monitor_pipe);
+       if (!notification_thread_handle) {
+               retval = -1;
+               ERR("Failed to create notification thread shared data");
+               stop_threads();
+               goto exit_notification;
        }
 
-       /* Create health-check thread */
-       ret = pthread_create(&health_thread, NULL,
-                       thread_manage_health, (void *) NULL);
-       if (ret != 0) {
-               PERROR("pthread_create health");
-               goto exit_health;
+       /* Create notification thread. */
+       ret = pthread_create(&notification_thread, default_pthread_attr(),
+                       thread_notification, notification_thread_handle);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create notification");
+               retval = -1;
+               stop_threads();
+               goto exit_notification;
        }
+       notification_thread_running = true;
 
        /* Create thread to manage the client socket */
-       ret = pthread_create(&client_thread, NULL,
+       ret = pthread_create(&client_thread, default_pthread_attr(),
                        thread_manage_clients, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create clients");
+               retval = -1;
+               stop_threads();
                goto exit_client;
        }
 
        /* Create thread to dispatch registration */
-       ret = pthread_create(&dispatch_thread, NULL,
+       ret = pthread_create(&dispatch_thread, default_pthread_attr(),
                        thread_dispatch_ust_registration, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create dispatch");
+               retval = -1;
+               stop_threads();
                goto exit_dispatch;
        }
 
        /* Create thread to manage application registration. */
-       ret = pthread_create(&reg_apps_thread, NULL,
+       ret = pthread_create(&reg_apps_thread, default_pthread_attr(),
                        thread_registration_apps, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create registration");
+               retval = -1;
+               stop_threads();
                goto exit_reg_apps;
        }
 
        /* Create thread to manage application socket */
-       ret = pthread_create(&apps_thread, NULL,
+       ret = pthread_create(&apps_thread, default_pthread_attr(),
                        thread_manage_apps, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create apps");
+               retval = -1;
+               stop_threads();
                goto exit_apps;
        }
 
        /* Create thread to manage application notify socket */
-       ret = pthread_create(&apps_notify_thread, NULL,
+       ret = pthread_create(&apps_notify_thread, default_pthread_attr(),
                        ust_thread_manage_notify, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create notify");
+               retval = -1;
+               stop_threads();
                goto exit_apps_notify;
        }
 
        /* Create agent registration thread. */
-       ret = pthread_create(&agent_reg_thread, NULL,
+       ret = pthread_create(&agent_reg_thread, default_pthread_attr(),
                        agent_thread_manage_registration, (void *) NULL);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_create agent");
+               retval = -1;
+               stop_threads();
                goto exit_agent_reg;
        }
 
        /* 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, NULL,
+               ret = pthread_create(&kernel_thread, default_pthread_attr(),
                                thread_manage_kernel, (void *) NULL);
-               if (ret != 0) {
+               if (ret) {
+                       errno = ret;
                        PERROR("pthread_create kernel");
+                       retval = -1;
+                       stop_threads();
                        goto exit_kernel;
                }
        }
 
-       /* Load possible session(s). */
-       start_load_session_thread();
+       /* Create session loading thread. */
+       ret = pthread_create(&load_session_thread, default_pthread_attr(),
+                       thread_load_session, load_info);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_create load_session_thread");
+               retval = -1;
+               stop_threads();
+               goto exit_load_session;
+       }
 
-       if (is_root && !opt_no_kernel) {
+       /*
+        * This is where we start awaiting program completion (e.g. through
+        * signal that asks threads to teardown).
+        */
+
+       ret = pthread_join(load_session_thread, &status);
+       if (ret) {
+               errno = ret;
+               PERROR("pthread_join load_session_thread");
+               retval = -1;
+       }
+exit_load_session:
+
+       if (is_root && !config.no_kernel) {
                ret = pthread_join(kernel_thread, &status);
-               if (ret != 0) {
+               if (ret) {
+                       errno = ret;
                        PERROR("pthread_join");
-                       goto error;     /* join error, exit without cleanup */
+                       retval = -1;
                }
        }
-
 exit_kernel:
+
        ret = pthread_join(agent_reg_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join agent");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_agent_reg:
+
        ret = pthread_join(apps_notify_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join apps notify");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_apps_notify:
+
        ret = pthread_join(apps_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join apps");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
-
 exit_apps:
+
        ret = pthread_join(reg_apps_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_reg_apps:
+
+       /*
+        * Join dispatch thread after joining reg_apps_thread to ensure
+        * we don't leak applications in the queue.
+        */
        ret = pthread_join(dispatch_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
-
 exit_dispatch:
+
        ret = pthread_join(client_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join");
-               goto error;     /* join error, exit without cleanup */
-       }
-
-       ret = join_consumer_thread(&kconsumer_data);
-       if (ret != 0) {
-               PERROR("join_consumer");
-               goto error;     /* join error, exit without cleanup */
-       }
-
-       ret = join_consumer_thread(&ustconsumer32_data);
-       if (ret != 0) {
-               PERROR("join_consumer ust32");
-               goto error;     /* join error, exit without cleanup */
-       }
-
-       ret = join_consumer_thread(&ustconsumer64_data);
-       if (ret != 0) {
-               PERROR("join_consumer ust64");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
 
 exit_client:
+exit_notification:
        ret = pthread_join(health_thread, &status);
-       if (ret != 0) {
+       if (ret) {
+               errno = ret;
                PERROR("pthread_join health thread");
-               goto error;     /* join error, exit without cleanup */
+               retval = -1;
        }
 
 exit_health:
-       ret = pthread_join(ht_cleanup_thread, &status);
-       if (ret != 0) {
-               PERROR("pthread_join ht cleanup thread");
-               goto error;     /* join error, exit without cleanup */
-       }
-exit_ht_cleanup:
-       health_app_destroy(health_sessiond);
-exit_health_sessiond_cleanup:
-exit:
+exit_init_data:
+       /*
+        * Wait for all pending call_rcu work to complete before tearing
+        * down data structures. call_rcu worker may be trying to
+        * perform lookups in those structures.
+        */
+       rcu_barrier();
        /*
-        * cleanup() is called when no other thread is running.
+        * sessiond_cleanup() is called when no other thread is running, except
+        * the ht_cleanup thread, which is needed to destroy the hash tables.
         */
        rcu_thread_online();
-       cleanup();
+       sessiond_cleanup();
+
+       /*
+        * Ensure all prior call_rcu are done. call_rcu callbacks may push
+        * hash tables to the ht_cleanup thread. Therefore, we ensure that
+        * the queue is empty before shutting down the clean-up thread.
+        */
+       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 (ret) {
+                               errno = ret;
+                               PERROR("pthread_join notification thread");
+                               retval = -1;
+                       }
+               }
+               notification_thread_handle_destroy(notification_thread_handle);
+       }
+
        rcu_thread_offline();
        rcu_unregister_thread();
-       if (!ret) {
+
+       ret = fini_ht_cleanup_thread(&ht_cleanup_thread);
+       if (ret) {
+               retval = -1;
+       }
+       lttng_pipe_destroy(ust32_channel_monitor_pipe);
+       lttng_pipe_destroy(ust64_channel_monitor_pipe);
+       lttng_pipe_destroy(kernel_channel_monitor_pipe);
+exit_ht_cleanup:
+
+       health_app_destroy(health_sessiond);
+exit_health_sessiond_cleanup:
+exit_create_run_as_worker_cleanup:
+
+exit_options:
+       sessiond_cleanup_options();
+
+exit_set_signal_handler:
+       if (!retval) {
                exit(EXIT_SUCCESS);
+       } else {
+               exit(EXIT_FAILURE);
        }
-error:
-       exit(EXIT_FAILURE);
 }
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