[lttng-tools.git] / src / bin / lttng-sessiond / consumer.c

/*
 * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License, version 2 only, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _GNU_SOURCE
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <inttypes.h>

#include <common/common.h>
#include <common/defaults.h>
#include <common/uri.h>
#include <common/utils.h>

#include "consumer.h"
#include "health.h"
#include "ust-app.h"
#include "utils.h"

/*
 * Receive a reply command status message from the consumer. Consumer socket
 * lock MUST be acquired before calling this function.
 *
 * Return 0 on success, -1 on recv error or a negative lttng error code which
 * was possibly returned by the consumer.
 */
int consumer_recv_status_reply(struct consumer_socket *sock)
{
        int ret;
        struct lttcomm_consumer_status_msg reply;

        assert(sock);

        ret = lttcomm_recv_unix_sock(sock->fd, &reply, sizeof(reply));
        if (ret <= 0) {
                if (ret == 0) {
                        /* Orderly shutdown. Don't return 0 which means success. */
                        ret = -1;
                }
                /* The above call will print a PERROR on error. */
                DBG("Fail to receive status reply on sock %d", sock->fd);
                goto end;
        }

        if (reply.ret_code == LTTNG_OK) {
                /* All good. */
                ret = 0;
        } else {
                ret = -reply.ret_code;
                DBG("Consumer ret code %d", ret);
        }

end:
        return ret;
}

/*
 * Once the ASK_CHANNEL command is sent to the consumer, the channel
 * information are sent back. This call receives that data and populates key
 * and stream_count.
 *
 * On success return 0 and both key and stream_count are set. On error, a
 * negative value is sent back and both parameters are untouched.
 */
int consumer_recv_status_channel(struct consumer_socket *sock,
                uint64_t *key, unsigned int *stream_count)
{
        int ret;
        struct lttcomm_consumer_status_channel reply;

        assert(sock);
        assert(stream_count);
        assert(key);

        ret = lttcomm_recv_unix_sock(sock->fd, &reply, sizeof(reply));
        if (ret <= 0) {
                if (ret == 0) {
                        /* Orderly shutdown. Don't return 0 which means success. */
                        ret = -1;
                }
                /* The above call will print a PERROR on error. */
                DBG("Fail to receive status reply on sock %d", sock->fd);
                goto end;
        }

        /* An error is possible so don't touch the key and stream_count. */
        if (reply.ret_code != LTTNG_OK) {
                ret = -1;
                goto end;
        }

        *key = reply.key;
        *stream_count = reply.stream_count;

end:
        return ret;
}

/*
 * Send destroy relayd command to consumer.
 *
 * On success return positive value. On error, negative value.
 */
int consumer_send_destroy_relayd(struct consumer_socket *sock,
                struct consumer_output *consumer)
{
        int ret;
        struct lttcomm_consumer_msg msg;

        assert(consumer);
        assert(sock);

        DBG2("Sending destroy relayd command to consumer sock %d", sock->fd);

        /* Bail out if consumer is disabled */
        if (!consumer->enabled) {
                ret = LTTNG_OK;
                DBG3("Consumer is disabled");
                goto error;
        }

        msg.cmd_type = LTTNG_CONSUMER_DESTROY_RELAYD;
        msg.u.destroy_relayd.net_seq_idx = consumer->net_seq_index;

        pthread_mutex_lock(sock->lock);
        ret = lttcomm_send_unix_sock(sock->fd, &msg, sizeof(msg));
        if (ret < 0) {
                /* Indicate that the consumer is probably closing at this point. */
                DBG("send consumer destroy relayd command");
                goto error_send;
        }

        /* Don't check the return value. The caller will do it. */
        ret = consumer_recv_status_reply(sock);

        DBG2("Consumer send destroy relayd command done");

error_send:
        pthread_mutex_unlock(sock->lock);
error:
        return ret;
}

/*
 * For each consumer socket in the consumer output object, send a destroy
 * relayd command.
 */
void consumer_output_send_destroy_relayd(struct consumer_output *consumer)
{
        struct lttng_ht_iter iter;
        struct consumer_socket *socket;

        assert(consumer);

        /* Destroy any relayd connection */
        if (consumer->type == CONSUMER_DST_NET) {
                rcu_read_lock();
                cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter, socket,
                                node.node) {
                        int ret;

                        /* Send destroy relayd command */
                        ret = consumer_send_destroy_relayd(socket, consumer);
                        if (ret < 0) {
                                DBG("Unable to send destroy relayd command to consumer");
                                /* Continue since we MUST delete everything at this point. */
                        }
                }
                rcu_read_unlock();
        }
}

/*
 * From a consumer_data structure, allocate and add a consumer socket to the
 * consumer output.
 *
 * Return 0 on success, else negative value on error
 */
int consumer_create_socket(struct consumer_data *data,
                struct consumer_output *output)
{
        int ret = 0;
        struct consumer_socket *socket;

        assert(data);

        if (output == NULL || data->cmd_sock < 0) {
                /*
                 * Not an error. Possible there is simply not spawned consumer or it's
                 * disabled for the tracing session asking the socket.
                 */
                goto error;
        }

        rcu_read_lock();
        socket = consumer_find_socket(data->cmd_sock, output);
        rcu_read_unlock();
        if (socket == NULL) {
                socket = consumer_allocate_socket(data->cmd_sock);
                if (socket == NULL) {
                        ret = -1;
                        goto error;
                }

                socket->registered = 0;
                socket->lock = &data->lock;
                rcu_read_lock();
                consumer_add_socket(socket, output);
                rcu_read_unlock();
        }

        socket->type = data->type;

        DBG3("Consumer socket created (fd: %d) and added to output",
                        data->cmd_sock);

error:
        return ret;
}

/*
 * Return the consumer socket from the given consumer output with the right
 * bitness. On error, returns NULL.
 *
 * The caller MUST acquire a rcu read side lock and keep it until the socket
 * object reference is not needed anymore.
 */
struct consumer_socket *consumer_find_socket_by_bitness(int bits,
                struct consumer_output *consumer)
{
        int consumer_fd;
        struct consumer_socket *socket = NULL;

        switch (bits) {
        case 64:
                consumer_fd = uatomic_read(&ust_consumerd64_fd);
                break;
        case 32:
                consumer_fd = uatomic_read(&ust_consumerd32_fd);
                break;
        default:
                assert(0);
                goto end;
        }

        socket = consumer_find_socket(consumer_fd, consumer);
        if (!socket) {
                ERR("Consumer socket fd %d not found in consumer obj %p",
                                consumer_fd, consumer);
        }

end:
        return socket;
}

/*
 * Find a consumer_socket in a consumer_output hashtable. Read side lock must
 * be acquired before calling this function and across use of the
 * returned consumer_socket.
 */
struct consumer_socket *consumer_find_socket(int key,
                struct consumer_output *consumer)
{
        struct lttng_ht_iter iter;
        struct lttng_ht_node_ulong *node;
        struct consumer_socket *socket = NULL;

        /* Negative keys are lookup failures */
        if (key < 0 || consumer == NULL) {
                return NULL;
        }

        lttng_ht_lookup(consumer->socks, (void *)((unsigned long) key),
                        &iter);
        node = lttng_ht_iter_get_node_ulong(&iter);
        if (node != NULL) {
                socket = caa_container_of(node, struct consumer_socket, node);
        }

        return socket;
}

/*
 * Allocate a new consumer_socket and return the pointer.
 */
struct consumer_socket *consumer_allocate_socket(int fd)
{
        struct consumer_socket *socket = NULL;

        socket = zmalloc(sizeof(struct consumer_socket));
        if (socket == NULL) {
                PERROR("zmalloc consumer socket");
                goto error;
        }

        socket->fd = fd;
        lttng_ht_node_init_ulong(&socket->node, fd);

error:
        return socket;
}

/*
 * Add consumer socket to consumer output object. Read side lock must be
 * acquired before calling this function.
 */
void consumer_add_socket(struct consumer_socket *sock,
                struct consumer_output *consumer)
{
        assert(sock);
        assert(consumer);

        lttng_ht_add_unique_ulong(consumer->socks, &sock->node);
}

/*
 * Delte consumer socket to consumer output object. Read side lock must be
 * acquired before calling this function.
 */
void consumer_del_socket(struct consumer_socket *sock,
                struct consumer_output *consumer)
{
        int ret;
        struct lttng_ht_iter iter;

        assert(sock);
        assert(consumer);

        iter.iter.node = &sock->node.node;
        ret = lttng_ht_del(consumer->socks, &iter);
        assert(!ret);
}

/*
 * RCU destroy call function.
 */
static void destroy_socket_rcu(struct rcu_head *head)
{
        struct lttng_ht_node_ulong *node =
                caa_container_of(head, struct lttng_ht_node_ulong, head);
        struct consumer_socket *socket =
                caa_container_of(node, struct consumer_socket, node);

        free(socket);
}

/*
 * Destroy and free socket pointer in a call RCU. Read side lock must be
 * acquired before calling this function.
 */
void consumer_destroy_socket(struct consumer_socket *sock)
{
        assert(sock);

        /*
         * We DO NOT close the file descriptor here since it is global to the
         * session daemon and is closed only if the consumer dies or a custom
         * consumer was registered,
         */
        if (sock->registered) {
                DBG3("Consumer socket was registered. Closing fd %d", sock->fd);
                lttcomm_close_unix_sock(sock->fd);
        }

        call_rcu(&sock->node.head, destroy_socket_rcu);
}

/*
 * Allocate and assign data to a consumer_output object.
 *
 * Return pointer to structure.
 */
struct consumer_output *consumer_create_output(enum consumer_dst_type type)
{
        struct consumer_output *output = NULL;

        output = zmalloc(sizeof(struct consumer_output));
        if (output == NULL) {
                PERROR("zmalloc consumer_output");
                goto error;
        }

        /* By default, consumer output is enabled */
        output->enabled = 1;
        output->type = type;
        output->net_seq_index = (uint64_t) -1ULL;

        output->socks = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);

error:
        return output;
}

/*
 * Delete the consumer_output object from the list and free the ptr.
 *
 * Should *NOT* be called with RCU read-side lock held.
 */
void consumer_destroy_output(struct consumer_output *obj)
{
        if (obj == NULL) {
                return;
        }

        if (obj->socks) {
                struct lttng_ht_iter iter;
                struct consumer_socket *socket;

                rcu_read_lock();
                cds_lfht_for_each_entry(obj->socks->ht, &iter.iter, socket, node.node) {
                        consumer_del_socket(socket, obj);
                        consumer_destroy_socket(socket);
                }
                rcu_read_unlock();

                /* Finally destroy HT */
                ht_cleanup_push(obj->socks);
        }

        free(obj);
}

/*
 * Copy consumer output and returned the newly allocated copy.
 *
 * Should *NOT* be called with RCU read-side lock held.
 */
struct consumer_output *consumer_copy_output(struct consumer_output *obj)
{
        int ret;
        struct lttng_ht *tmp_ht_ptr;
        struct consumer_output *output;

        assert(obj);

        output = consumer_create_output(obj->type);
        if (output == NULL) {
                goto error;
        }
        /* Avoid losing the HT reference after the memcpy() */
        tmp_ht_ptr = output->socks;

        memcpy(output, obj, sizeof(struct consumer_output));

        /* Putting back the HT pointer and start copying socket(s). */
        output->socks = tmp_ht_ptr;

        ret = consumer_copy_sockets(output, obj);
        if (ret < 0) {
                goto malloc_error;
        }

error:
        return output;

malloc_error:
        consumer_destroy_output(output);
        return NULL;
}

/*
 * Copy consumer sockets from src to dst.
 *
 * Return 0 on success or else a negative value.
 */
int consumer_copy_sockets(struct consumer_output *dst,
                struct consumer_output *src)
{
        int ret = 0;
        struct lttng_ht_iter iter;
        struct consumer_socket *socket, *copy_sock;

        assert(dst);
        assert(src);

        rcu_read_lock();
        cds_lfht_for_each_entry(src->socks->ht, &iter.iter, socket, node.node) {
                /* Ignore socket that are already there. */
                copy_sock = consumer_find_socket(socket->fd, dst);
                if (copy_sock) {
                        continue;
                }

                /* Create new socket object. */
                copy_sock = consumer_allocate_socket(socket->fd);
                if (copy_sock == NULL) {
                        rcu_read_unlock();
                        ret = -ENOMEM;
                        goto error;
                }

                copy_sock->registered = socket->registered;
                /*
                 * This is valid because this lock is shared accross all consumer
                 * object being the global lock of the consumer data structure of the
                 * session daemon.
                 */
                copy_sock->lock = socket->lock;
                consumer_add_socket(copy_sock, dst);
        }
        rcu_read_unlock();

error:
        return ret;
}

/*
 * Set network URI to the consumer output object.
 *
 * Return 0 on success. Return 1 if the URI were equal. Else, negative value on
 * error.
 */
int consumer_set_network_uri(struct consumer_output *obj,
                struct lttng_uri *uri)
{
        int ret;
        char tmp_path[PATH_MAX];
        char hostname[HOST_NAME_MAX];
        struct lttng_uri *dst_uri = NULL;

        /* Code flow error safety net. */
        assert(obj);
        assert(uri);

        switch (uri->stype) {
        case LTTNG_STREAM_CONTROL:
                dst_uri = &obj->dst.net.control;
                obj->dst.net.control_isset = 1;
                if (uri->port == 0) {
                        /* Assign default port. */
                        uri->port = DEFAULT_NETWORK_CONTROL_PORT;
                } else {
                        if (obj->dst.net.data_isset && uri->port ==
                                        obj->dst.net.data.port) {
                                ret = -LTTNG_ERR_INVALID;
                                goto error;
                        }
                }
                DBG3("Consumer control URI set with port %d", uri->port);
                break;
        case LTTNG_STREAM_DATA:
                dst_uri = &obj->dst.net.data;
                obj->dst.net.data_isset = 1;
                if (uri->port == 0) {
                        /* Assign default port. */
                        uri->port = DEFAULT_NETWORK_DATA_PORT;
                } else {
                        if (obj->dst.net.control_isset && uri->port ==
                                        obj->dst.net.control.port) {
                                ret = -LTTNG_ERR_INVALID;
                                goto error;
                        }
                }
                DBG3("Consumer data URI set with port %d", uri->port);
                break;
        default:
                ERR("Set network uri type unknown %d", uri->stype);
                ret = -LTTNG_ERR_INVALID;
                goto error;
        }

        ret = uri_compare(dst_uri, uri);
        if (!ret) {
                /* Same URI, don't touch it and return success. */
                DBG3("URI network compare are the same");
                goto equal;
        }

        /* URIs were not equal, replacing it. */
        memset(dst_uri, 0, sizeof(struct lttng_uri));
        memcpy(dst_uri, uri, sizeof(struct lttng_uri));
        obj->type = CONSUMER_DST_NET;

        /* Handle subdir and add hostname in front. */
        if (dst_uri->stype == LTTNG_STREAM_CONTROL) {
                /* Get hostname to append it in the pathname */
                ret = gethostname(hostname, sizeof(hostname));
                if (ret < 0) {
                        PERROR("gethostname. Fallback on default localhost");
                        strncpy(hostname, "localhost", sizeof(hostname));
                }
                hostname[sizeof(hostname) - 1] = '\0';

                /* Setup consumer subdir if none present in the control URI */
                if (strlen(dst_uri->subdir) == 0) {
                        ret = snprintf(tmp_path, sizeof(tmp_path), "%s/%s",
                                        hostname, obj->subdir);
                } else {
                        ret = snprintf(tmp_path, sizeof(tmp_path), "%s/%s",
                                        hostname, dst_uri->subdir);
                }
                if (ret < 0) {
                        PERROR("snprintf set consumer uri subdir");
                        ret = -LTTNG_ERR_NOMEM;
                        goto error;
                }

                strncpy(obj->subdir, tmp_path, sizeof(obj->subdir));
                DBG3("Consumer set network uri subdir path %s", tmp_path);
        }

        return 0;
equal:
        return 1;
error:
        return ret;
}

/*
 * Send file descriptor to consumer via sock.
 */
int consumer_send_fds(struct consumer_socket *sock, int *fds, size_t nb_fd)
{
        int ret;

        assert(fds);
        assert(sock);
        assert(nb_fd > 0);

        ret = lttcomm_send_fds_unix_sock(sock->fd, fds, nb_fd);
        if (ret < 0) {
                /* The above call will print a PERROR on error. */
                DBG("Error when sending consumer fds on sock %d", sock->fd);
                goto error;
        }

        ret = consumer_recv_status_reply(sock);

error:
        return ret;
}

/*
 * Consumer send communication message structure to consumer.
 */
int consumer_send_msg(struct consumer_socket *sock,
                struct lttcomm_consumer_msg *msg)
{
        int ret;

        assert(msg);
        assert(sock);
        assert(sock->fd >= 0);

        ret = lttcomm_send_unix_sock(sock->fd, msg,
                        sizeof(struct lttcomm_consumer_msg));
        if (ret < 0) {
                /* The above call will print a PERROR on error. */
                DBG("Error when sending consumer channel on sock %d", sock->fd);
                goto error;
        }

        ret = consumer_recv_status_reply(sock);

error:
        return ret;
}

/*
 * Consumer send channel communication message structure to consumer.
 */
int consumer_send_channel(struct consumer_socket *sock,
                struct lttcomm_consumer_msg *msg)
{
        int ret;

        assert(msg);
        assert(sock);
        assert(sock->fd >= 0);

        ret = lttcomm_send_unix_sock(sock->fd, msg,
                        sizeof(struct lttcomm_consumer_msg));
        if (ret < 0) {
                /* The above call will print a PERROR on error. */
                DBG("Error when sending consumer channel on sock %d", sock->fd);
                goto error;
        }

        ret = consumer_recv_status_reply(sock);

error:
        return ret;
}

/*
 * Populate the given consumer msg structure with the ask_channel command
 * information.
 */
void consumer_init_ask_channel_comm_msg(struct lttcomm_consumer_msg *msg,
                uint64_t subbuf_size,
                uint64_t num_subbuf,
                int overwrite,
                unsigned int switch_timer_interval,
                unsigned int read_timer_interval,
                int output,
                int type,
                uint64_t session_id,
                const char *pathname,
                const char *name,
                uid_t uid,
                gid_t gid,
                uint64_t relayd_id,
                uint64_t key,
                unsigned char *uuid,
                uint32_t chan_id,
                uint64_t tracefile_size,
                uint64_t tracefile_count,
                unsigned int monitor)
{
        assert(msg);

        /* Zeroed structure */
        memset(msg, 0, sizeof(struct lttcomm_consumer_msg));

        msg->cmd_type = LTTNG_CONSUMER_ASK_CHANNEL_CREATION;
        msg->u.ask_channel.subbuf_size = subbuf_size;
        msg->u.ask_channel.num_subbuf = num_subbuf ;
        msg->u.ask_channel.overwrite = overwrite;
        msg->u.ask_channel.switch_timer_interval = switch_timer_interval;
        msg->u.ask_channel.read_timer_interval = read_timer_interval;
        msg->u.ask_channel.output = output;
        msg->u.ask_channel.type = type;
        msg->u.ask_channel.session_id = session_id;
        msg->u.ask_channel.uid = uid;
        msg->u.ask_channel.gid = gid;
        msg->u.ask_channel.relayd_id = relayd_id;
        msg->u.ask_channel.key = key;
        msg->u.ask_channel.chan_id = chan_id;
        msg->u.ask_channel.tracefile_size = tracefile_size;
        msg->u.ask_channel.tracefile_count = tracefile_count;
        msg->u.ask_channel.monitor = monitor;

        memcpy(msg->u.ask_channel.uuid, uuid, sizeof(msg->u.ask_channel.uuid));

        strncpy(msg->u.ask_channel.pathname, pathname,
                        sizeof(msg->u.ask_channel.pathname));
        msg->u.ask_channel.pathname[sizeof(msg->u.ask_channel.pathname)-1] = '\0';

        strncpy(msg->u.ask_channel.name, name, sizeof(msg->u.ask_channel.name));
        msg->u.ask_channel.name[sizeof(msg->u.ask_channel.name) - 1] = '\0';
}

/*
 * Init channel communication message structure.
 */
void consumer_init_channel_comm_msg(struct lttcomm_consumer_msg *msg,
                enum lttng_consumer_command cmd,
                uint64_t channel_key,
                uint64_t session_id,
                const char *pathname,
                uid_t uid,
                gid_t gid,
                uint64_t relayd_id,
                const char *name,
                unsigned int nb_init_streams,
                enum lttng_event_output output,
                int type,
                uint64_t tracefile_size,
                uint64_t tracefile_count,
                unsigned int monitor)
{
        assert(msg);

        /* Zeroed structure */
        memset(msg, 0, sizeof(struct lttcomm_consumer_msg));

        /* Send channel */
        msg->cmd_type = cmd;
        msg->u.channel.channel_key = channel_key;
        msg->u.channel.session_id = session_id;
        msg->u.channel.uid = uid;
        msg->u.channel.gid = gid;
        msg->u.channel.relayd_id = relayd_id;
        msg->u.channel.nb_init_streams = nb_init_streams;
        msg->u.channel.output = output;
        msg->u.channel.type = type;
        msg->u.channel.tracefile_size = tracefile_size;
        msg->u.channel.tracefile_count = tracefile_count;
        msg->u.channel.monitor = monitor;

        strncpy(msg->u.channel.pathname, pathname,
                        sizeof(msg->u.channel.pathname));
        msg->u.channel.pathname[sizeof(msg->u.channel.pathname) - 1] = '\0';

        strncpy(msg->u.channel.name, name, sizeof(msg->u.channel.name));
        msg->u.channel.name[sizeof(msg->u.channel.name) - 1] = '\0';
}

/*
 * Init stream communication message structure.
 */
void consumer_init_stream_comm_msg(struct lttcomm_consumer_msg *msg,
                enum lttng_consumer_command cmd,
                uint64_t channel_key,
                uint64_t stream_key,
                int cpu)
{
        assert(msg);

        memset(msg, 0, sizeof(struct lttcomm_consumer_msg));

        msg->cmd_type = cmd;
        msg->u.stream.channel_key = channel_key;
        msg->u.stream.stream_key = stream_key;
        msg->u.stream.cpu = cpu;
}

/*
 * Send stream communication structure to the consumer.
 */
int consumer_send_stream(struct consumer_socket *sock,
                struct consumer_output *dst, struct lttcomm_consumer_msg *msg,
                int *fds, size_t nb_fd)
{
        int ret;

        assert(msg);
        assert(dst);
        assert(sock);
        assert(fds);

        /* Send on socket */
        ret = lttcomm_send_unix_sock(sock->fd, msg,
                        sizeof(struct lttcomm_consumer_msg));
        if (ret < 0) {
                /* The above call will print a PERROR on error. */
                DBG("Error when sending consumer stream on sock %d", sock->fd);
                goto error;
        }

        ret = consumer_recv_status_reply(sock);
        if (ret < 0) {
                goto error;
        }

        ret = consumer_send_fds(sock, fds, nb_fd);
        if (ret < 0) {
                goto error;
        }

error:
        return ret;
}

/*
 * Send relayd socket to consumer associated with a session name.
 *
 * On success return positive value. On error, negative value.
 */
int consumer_send_relayd_socket(struct consumer_socket *consumer_sock,
                struct lttcomm_relayd_sock *rsock, struct consumer_output *consumer,
                enum lttng_stream_type type, uint64_t session_id)
{
        int ret;
        struct lttcomm_consumer_msg msg;

        /* Code flow error. Safety net. */
        assert(rsock);
        assert(consumer);
        assert(consumer_sock);

        /* Bail out if consumer is disabled */
        if (!consumer->enabled) {
                ret = LTTNG_OK;
                goto error;
        }

        msg.cmd_type = LTTNG_CONSUMER_ADD_RELAYD_SOCKET;
        /*
         * Assign network consumer output index using the temporary consumer since
         * this call should only be made from within a set_consumer_uri() function
         * call in the session daemon.
         */
        msg.u.relayd_sock.net_index = consumer->net_seq_index;
        msg.u.relayd_sock.type = type;
        msg.u.relayd_sock.session_id = session_id;
        memcpy(&msg.u.relayd_sock.sock, rsock, sizeof(msg.u.relayd_sock.sock));

        DBG3("Sending relayd sock info to consumer on %d", consumer_sock->fd);
        ret = lttcomm_send_unix_sock(consumer_sock->fd, &msg, sizeof(msg));
        if (ret < 0) {
                /* The above call will print a PERROR on error. */
                DBG("Error when sending relayd sockets on sock %d", rsock->sock.fd);
                goto error;
        }

        ret = consumer_recv_status_reply(consumer_sock);
        if (ret < 0) {
                goto error;
        }

        DBG3("Sending relayd socket file descriptor to consumer");
        ret = consumer_send_fds(consumer_sock, &rsock->sock.fd, 1);
        if (ret < 0) {
                goto error;
        }

        DBG2("Consumer relayd socket sent");

error:
        return ret;
}

/*
 * Set consumer subdirectory using the session name and a generated datetime if
 * needed. This is appended to the current subdirectory.
 */
int consumer_set_subdir(struct consumer_output *consumer,
                const char *session_name)
{
        int ret = 0;
        unsigned int have_default_name = 0;
        char datetime[16], tmp_path[PATH_MAX];
        time_t rawtime;
        struct tm *timeinfo;

        assert(consumer);
        assert(session_name);

        memset(tmp_path, 0, sizeof(tmp_path));

        /* Flag if we have a default session. */
        if (strncmp(session_name, DEFAULT_SESSION_NAME "-",
                                strlen(DEFAULT_SESSION_NAME) + 1) == 0) {
                have_default_name = 1;
        } else {
                /* Get date and time for session path */
                time(&rawtime);
                timeinfo = localtime(&rawtime);
                strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
        }

        if (have_default_name) {
                ret = snprintf(tmp_path, sizeof(tmp_path),
                                "%s/%s", consumer->subdir, session_name);
        } else {
                ret = snprintf(tmp_path, sizeof(tmp_path),
                                "%s/%s-%s/", consumer->subdir, session_name, datetime);
        }
        if (ret < 0) {
                PERROR("snprintf session name date");
                goto error;
        }

        strncpy(consumer->subdir, tmp_path, sizeof(consumer->subdir));
        DBG2("Consumer subdir set to %s", consumer->subdir);

error:
        return ret;
}

/*
 * Ask the consumer if the data is ready to read (NOT pending) for the specific
 * session id.
 *
 * This function has a different behavior with the consumer i.e. that it waits
 * for a reply from the consumer if yes or no the data is pending.
 */
int consumer_is_data_pending(uint64_t session_id,
                struct consumer_output *consumer)
{
        int ret;
        int32_t ret_code = 0;  /* Default is that the data is NOT pending */
        struct consumer_socket *socket;
        struct lttng_ht_iter iter;
        struct lttcomm_consumer_msg msg;

        assert(consumer);

        msg.cmd_type = LTTNG_CONSUMER_DATA_PENDING;

        msg.u.data_pending.session_id = session_id;

        DBG3("Consumer data pending for id %" PRIu64, session_id);

        /* Send command for each consumer */
        rcu_read_lock();
        cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter, socket,
                        node.node) {
                /* Code flow error */
                assert(socket->fd >= 0);

                pthread_mutex_lock(socket->lock);

                ret = lttcomm_send_unix_sock(socket->fd, &msg, sizeof(msg));
                if (ret < 0) {
                        /* The above call will print a PERROR on error. */
                        DBG("Error on consumer is data pending on sock %d", socket->fd);
                        pthread_mutex_unlock(socket->lock);
                        goto error_unlock;
                }

                /*
                 * No need for a recv reply status because the answer to the command is
                 * the reply status message.
                 */

                ret = lttcomm_recv_unix_sock(socket->fd, &ret_code, sizeof(ret_code));
                if (ret <= 0) {
                        if (ret == 0) {
                                /* Orderly shutdown. Don't return 0 which means success. */
                                ret = -1;
                        }
                        /* The above call will print a PERROR on error. */
                        DBG("Error on recv consumer is data pending on sock %d", socket->fd);
                        pthread_mutex_unlock(socket->lock);
                        goto error_unlock;
                }

                pthread_mutex_unlock(socket->lock);

                if (ret_code == 1) {
                        break;
                }
        }
        rcu_read_unlock();

        DBG("Consumer data is %s pending for session id %" PRIu64,
                        ret_code == 1 ? "" : "NOT", session_id);
        return ret_code;

error_unlock:
        rcu_read_unlock();
        return -1;
}

/*
 * Send a flush command to consumer using the given channel key.
 *
 * Return 0 on success else a negative value.
 */
int consumer_flush_channel(struct consumer_socket *socket, uint64_t key)
{
        int ret;
        struct lttcomm_consumer_msg msg;

        assert(socket);
        assert(socket->fd >= 0);

        DBG2("Consumer flush channel key %" PRIu64, key);

        msg.cmd_type = LTTNG_CONSUMER_FLUSH_CHANNEL;
        msg.u.flush_channel.key = key;

        pthread_mutex_lock(socket->lock);
        health_code_update();

        ret = consumer_send_msg(socket, &msg);
        if (ret < 0) {
                goto end;
        }

end:
        health_code_update();
        pthread_mutex_unlock(socket->lock);
        return ret;
}

/*
 * Send a close metdata command to consumer using the given channel key.
 *
 * Return 0 on success else a negative value.
 */
int consumer_close_metadata(struct consumer_socket *socket,
                uint64_t metadata_key)
{
        int ret;
        struct lttcomm_consumer_msg msg;

        assert(socket);
        assert(socket->fd >= 0);

        DBG2("Consumer close metadata channel key %" PRIu64, metadata_key);

        msg.cmd_type = LTTNG_CONSUMER_CLOSE_METADATA;
        msg.u.close_metadata.key = metadata_key;

        pthread_mutex_lock(socket->lock);
        health_code_update();

        ret = consumer_send_msg(socket, &msg);
        if (ret < 0) {
                goto end;
        }

end:
        health_code_update();
        pthread_mutex_unlock(socket->lock);
        return ret;
}

/*
 * Send a setup metdata command to consumer using the given channel key.
 *
 * Return 0 on success else a negative value.
 */
int consumer_setup_metadata(struct consumer_socket *socket,
                uint64_t metadata_key)
{
        int ret;
        struct lttcomm_consumer_msg msg;

        assert(socket);
        assert(socket->fd >= 0);

        DBG2("Consumer setup metadata channel key %" PRIu64, metadata_key);

        msg.cmd_type = LTTNG_CONSUMER_SETUP_METADATA;
        msg.u.setup_metadata.key = metadata_key;

        pthread_mutex_lock(socket->lock);
        health_code_update();

        ret = consumer_send_msg(socket, &msg);
        if (ret < 0) {
                goto end;
        }

end:
        health_code_update();
        pthread_mutex_unlock(socket->lock);
        return ret;
}

/*
 * Send metadata string to consumer. Socket lock MUST be acquired.
 *
 * Return 0 on success else a negative value.
 */
int consumer_push_metadata(struct consumer_socket *socket,
                uint64_t metadata_key, char *metadata_str, size_t len,
                size_t target_offset)
{
        int ret;
        struct lttcomm_consumer_msg msg;

        assert(socket);
        assert(socket->fd >= 0);

        DBG2("Consumer push metadata to consumer socket %d", socket->fd);

        msg.cmd_type = LTTNG_CONSUMER_PUSH_METADATA;
        msg.u.push_metadata.key = metadata_key;
        msg.u.push_metadata.target_offset = target_offset;
        msg.u.push_metadata.len = len;

        health_code_update();
        ret = consumer_send_msg(socket, &msg);
        if (ret < 0 || len == 0) {
                goto end;
        }

        DBG3("Consumer pushing metadata on sock %d of len %zu", socket->fd, len);

        ret = lttcomm_send_unix_sock(socket->fd, metadata_str, len);
        if (ret < 0) {
                goto end;
        }

        health_code_update();
        ret = consumer_recv_status_reply(socket);
        if (ret < 0) {
                goto end;
        }

end:
        health_code_update();
        return ret;
}

/*
 * Ask the consumer to snapshot a specific channel using the key.
 *
 * Return 0 on success or else a negative error.
 */
int consumer_snapshot_channel(struct consumer_socket *socket, uint64_t key,
                struct snapshot_output *output, int metadata, uid_t uid, gid_t gid,
                const char *session_path, int wait)
{
        int ret;
        char datetime[16];
        struct lttcomm_consumer_msg msg;

        assert(socket);
        assert(socket->fd >= 0);
        assert(output);
        assert(output->consumer);

        DBG("Consumer snapshot channel key %" PRIu64, key);

        ret = utils_get_current_time_str("%Y%m%d-%H%M%S", datetime,
                        sizeof(datetime));
        if (!ret) {
                ret = -EINVAL;
                goto error;
        }

        memset(&msg, 0, sizeof(msg));
        msg.cmd_type = LTTNG_CONSUMER_SNAPSHOT_CHANNEL;
        msg.u.snapshot_channel.key = key;
        msg.u.snapshot_channel.max_size = output->max_size;
        msg.u.snapshot_channel.metadata = metadata;

        if (output->consumer->type == CONSUMER_DST_NET) {
                msg.u.snapshot_channel.relayd_id = output->consumer->net_seq_index;
                msg.u.snapshot_channel.use_relayd = 1;
                ret = snprintf(msg.u.snapshot_channel.pathname,
                                sizeof(msg.u.snapshot_channel.pathname), "%s/%s-%s%s",
                                output->consumer->subdir, output->name, datetime,
                                session_path);
                if (ret < 0) {
                        ret = -LTTNG_ERR_NOMEM;
                        goto error;
                }
        } else {
                ret = snprintf(msg.u.snapshot_channel.pathname,
                                sizeof(msg.u.snapshot_channel.pathname), "%s/%s-%s%s",
                                output->consumer->dst.trace_path, output->name, datetime,
                                session_path);
                if (ret < 0) {
                        ret = -LTTNG_ERR_NOMEM;
                        goto error;
                }
                msg.u.snapshot_channel.relayd_id = (uint64_t) -1ULL;

                /* Create directory. Ignore if exist. */
                ret = run_as_mkdir_recursive(msg.u.snapshot_channel.pathname,
                                S_IRWXU | S_IRWXG, uid, gid);
                if (ret < 0) {
                        if (ret != -EEXIST) {
                                ERR("Trace directory creation error");
                                goto error;
                        }
                }
        }

        health_code_update();
        ret = consumer_send_msg(socket, &msg);
        if (ret < 0) {
                goto error;
        }

error:
        health_code_update();
        return ret;
}