Add mutex protection for the traceable apps

[lttng-tools.git] / ltt-sessiond / ltt-sessiond.c

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#define _GNU_SOURCE
#include <fcntl.h>
#include <getopt.h>
#include <grp.h>
#include <limits.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include <urcu/list.h>          /* URCU list library (-lurcu) */
#include <ust/ustctl.h>         /* UST control lib (-lust) */
#include <lttng/liblttngctl.h>

#include "liblttsessiondcomm.h"
#include "ltt-sessiond.h"
#include "lttngerr.h"

/* Const values */
const char default_home_dir[] = DEFAULT_HOME_DIR;
const char default_tracing_group[] = DEFAULT_TRACING_GROUP;
const char default_ust_sock_dir[] = DEFAULT_UST_SOCK_DIR;
const char default_global_apps_pipe[] = DEFAULT_GLOBAL_APPS_PIPE;

/* Static functions */
static int set_signal_handler(void);
static int set_socket_perms(void);
static void sighandler(int sig);
static void cleanup(void);
static void copy_common_data(struct lttcomm_lttng_msg *llm, struct lttcomm_session_msg *lsm);
static int check_existing_daemon(void);
static int notify_apps(const char* name);
static int connect_app(pid_t pid);
static int find_app_by_pid(pid_t pid);
static int init_daemon_socket(void);
static int process_client_msg(int sock, struct lttcomm_session_msg*);
static int send_unix_sock(int sock, void *buf, size_t len);
static int setup_data_buffer(char **buf, size_t size, struct lttcomm_lttng_msg *llm);
static void add_traceable_app(struct ltt_traceable_app *lta);
static void del_traceable_app(struct ltt_traceable_app *lta);
static void add_session_list(struct ltt_session *ls);
static void del_session_list(struct ltt_session *ls);

/* Command function */
static void get_list_apps(pid_t *pids);
static void get_list_sessions(struct lttng_session *lt);

static void *thread_manage_clients(void *data);
static void *thread_manage_apps(void *data);

static int create_session(char *name, uuid_t *session_id);
static int destroy_session(uuid_t *uuid);

static struct ltt_session *find_session_by_uuid(uuid_t session_id);
static struct ltt_session *find_session_by_name(char *name);

/* Variables */
const char *progname;
const char *opt_tracing_group;
static int opt_sig_parent;
static int opt_daemon;
int opt_verbose;
int opt_quiet;
static int is_root;                     /* Set to 1 if the daemon is running as root */
static pid_t ppid;

static char apps_unix_sock_path[PATH_MAX];                      /* Global application Unix socket path */
static char client_unix_sock_path[PATH_MAX];            /* Global client Unix socket path */

static int client_socket;
static int apps_socket;

static struct ltt_session *current_session;

/* Number of element for the list below. */
static unsigned int session_count;
static unsigned int traceable_app_count;

/* Init session's list */
static struct ltt_session_list ltt_session_list = {
        .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
};

/* Init ust traceabl application's list */
static struct ltt_traceable_app_list ltt_traceable_app_list = {
        .head = CDS_LIST_HEAD_INIT(ltt_traceable_app_list.head),
};

/* List mutex */
pthread_mutex_t ltt_traceable_app_list_mutex;

/*
 *      thread_manage_apps
 *
 *      This thread manage the application socket communication
 */
static void *thread_manage_apps(void *data)
{
        int sock, ret;
        struct ltt_traceable_app *lta;

        /* TODO: Something more elegant is needed but fine for now */
        struct {
                int reg;        /* 1:register, 0:unregister */
                pid_t pid;
                uid_t uid;
        } reg_msg;

        /* Notify all applications to register */
        notify_apps(default_global_apps_pipe);

        ret = lttcomm_listen_unix_sock(apps_socket);
        if (ret < 0) {
                goto error;
        }

        while (1) {
                /* Blocking call, waiting for transmission */
                sock = lttcomm_accept_unix_sock(apps_socket);
                if (sock < 0) {
                        goto error;
                }

                /* Basic recv here to handle the very simple data
                 * that the libust send to register (reg_msg).
                 */
                ret = recv(sock, &reg_msg, sizeof(reg_msg), 0);
                if (ret < 0) {
                        perror("recv");
                        continue;
                }

                /* Add application to the global traceable list */
                if (reg_msg.reg == 1) {
                        /* Registering */
                        lta = malloc(sizeof(struct ltt_traceable_app));
                        lta->pid = reg_msg.pid;
                        lta->uid = reg_msg.uid;
                        add_traceable_app(lta);
                } else {
                        /* Unregistering */
                        cds_list_for_each_entry(lta, &ltt_traceable_app_list.head, list) {
                                if (lta->pid == reg_msg.pid && lta->uid == reg_msg.uid) {
                                        del_traceable_app(lta);
                                        free(lta);
                                        break;
                                }
                        }
                }
        }

error:

        return NULL;
}

/*
 *      thread_manage_clients
 *
 *      This thread manage all clients request using the unix
 *      client socket for communication.
 */
static void *thread_manage_clients(void *data)
{
        int sock, ret;
        struct lttcomm_session_msg lsm;

        ret = lttcomm_listen_unix_sock(client_socket);
        if (ret < 0) {
                goto error;
        }

        /* Notify parent pid that we are ready
         * to accept command for client side.
         */
        if (opt_sig_parent) {
                kill(ppid, SIGCHLD);
        }

        while (1) {
                /* Blocking call, waiting for transmission */
                sock = lttcomm_accept_unix_sock(client_socket);
                if (sock < 0) {
                        goto error;
                }

                /*
                 * Data is received from the lttng client. The struct
                 * lttcomm_session_msg (lsm) contains the command and data
                 * request of the client.
                 */
                ret = lttcomm_recv_unix_sock(sock, &lsm, sizeof(lsm));
                if (ret <= 0) {
                        continue;
                }

                /* This function dispatch the work to the LTTng or UST libs
                 * and then sends back the response to the client. This is needed
                 * because there might be more then one lttcomm_lttng_msg to
                 * send out so process_client_msg do both jobs.
                 */
                ret = process_client_msg(sock, &lsm);
                if (ret < 0) {
                        /* Error detected but still accept command */
                        continue;
                }
        }

error:
        return NULL;
}

/*
 *  add_traceable_app
 *
 *  Add a traceable application structure to the global
 *  list protected by a mutex.
 */
static void add_traceable_app(struct ltt_traceable_app *lta)
{
        pthread_mutex_lock(&ltt_traceable_app_list_mutex);
        cds_list_add(&lta->list, &ltt_traceable_app_list.head);
        traceable_app_count++;
        pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
}

/*
 *  del_traceable_app
 *
 *  Delete a traceable application structure from the
 *  global list protected by a mutex.
 */
static void del_traceable_app(struct ltt_traceable_app *lta)
{
        pthread_mutex_lock(&ltt_traceable_app_list_mutex);
        cds_list_del(&lta->list);
        /* Sanity check */
        if (traceable_app_count != 0) {
                traceable_app_count--;
        }
        pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
}

/*
 *  add_session_list
 *
 *  Add a ltt_session structure to the global list.
 */
static void add_session_list(struct ltt_session *ls)
{
        cds_list_add(&ls->list, &ltt_session_list.head);
        session_count++;
}

/*
 *  del_session_list
 *
 *  Delete a ltt_session structure to the global list.
 */
static void del_session_list(struct ltt_session *ls)
{
        cds_list_del(&ls->list);
        /* Sanity check */
        if (session_count != 0) {
                session_count--;
        }
}

/*
 *  send_unix_sock
 *
 *  Send data on a unix socket using the liblttsessiondcomm API.
 *
 *  Return lttcomm error code.
 */
static int send_unix_sock(int sock, void *buf, size_t len)
{
        /* Check valid length */
        if (len <= 0) {
                return -1;
        }

        return lttcomm_send_unix_sock(sock, buf, len);
}

/*
 *      connect_app
 *
 *      Return a socket connected to the libust communication socket
 *      of the application identified by the pid.
 *
 *      If the pid is not found in the traceable list,
 *      return -1 to indicate error.
 */
static int connect_app(pid_t pid)
{
        int sock, ret;

        ret = find_app_by_pid(pid);
        if (ret == 0) {
                return -1;
        }

        sock = ustctl_connect_pid(pid);
        if (sock < 0) {
                ERR("Fail connecting to the PID %d\n", pid);
        }

        return sock;
}

/*
 *      notify_apps
 *
 *  Notify apps by writing 42 to a named pipe using name.
 *      Every applications waiting for a ltt-sessiond will be notified
 *      and re-register automatically to the session daemon.
 *
 *      Return open or write error value.
 */
static int notify_apps(const char *name)
{
        int fd;
        int ret = -1;

        /* Try opening the global pipe */
        fd = open(name, O_WRONLY);
        if (fd < 0) {
                goto error;
        }

        /* Notify by writing on the pipe */
        ret = write(fd, "42", 2);
        if (ret < 0) {
                perror("write");
        }

error:
        return ret;
}

/*
 *  find_app_by_pid
 *
 *  Iterate over the traceable apps list.
 *  On success, return 1, else return 0
 */
static int find_app_by_pid(pid_t pid)
{
        struct ltt_traceable_app *iter;

        pthread_mutex_lock(&ltt_traceable_app_list_mutex);
        cds_list_for_each_entry(iter, &ltt_traceable_app_list.head, list) {
                if (iter->pid == pid) {
                        pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
                        /* Found */
                        return 1;
                }
        }
        pthread_mutex_unlock(&ltt_traceable_app_list_mutex);

        return 0;
}

/*
 *      find_session_by_uuid
 *
 *      Return a ltt_session structure ptr that matches the uuid.
 */
static struct ltt_session *find_session_by_uuid(uuid_t session_id)
{
        int found = 0;
        struct ltt_session *iter;

        /* Sanity check for NULL session_id */
        if (uuid_is_null(session_id)) {
                goto end;
        }

        cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
                if (uuid_compare(iter->uuid, session_id) == 0) {
                        found = 1;
                        break;
                }
        }

end:
        if (!found) {
                iter = NULL;
        }
        return iter;
}

/*
 *      find_session_by_name
 *
 *      Return a ltt_session structure ptr that matches name.
 *      If no session found, NULL is returned.
 */
static struct ltt_session *find_session_by_name(char *name)
{
        int found = 0;
        struct ltt_session *iter;

        cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
                if (strncmp(iter->name, name, strlen(iter->name)) == 0) {
                        found = 1;
                        break;
                }
        }

        if (!found) {
                iter = NULL;
        }

        return iter;
}

/*
 *      destroy_session
 *
 *  Delete session from the global session list
 *  and free the memory.
 *
 *  Return -1 if no session is found.
 *  On success, return 1;
 */
static int destroy_session(uuid_t *uuid)
{
        int found = -1;
        struct ltt_session *iter;

        cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
                if (uuid_compare(iter->uuid, *uuid) == 0) {
                        del_session_list(iter);
                        free(iter);
                        found = 1;
                        break;
                }
        }

        return found;
}

/*
 *      create_session
 *
 *      Create a brand new session and add it to the
 *      global session list.
 */
static int create_session(char *name, uuid_t *session_id)
{
        struct ltt_session *new_session;

        /* Allocate session data structure */
        new_session = malloc(sizeof(struct ltt_session));
        if (new_session == NULL) {
                perror("malloc");
                goto error;
        }

        if (name != NULL) {
                if (asprintf(&new_session->name, "%s", name) < 0) {
                        goto error;
                }
        } else {
                /* Generate session name based on the session count */
                if (asprintf(&new_session->name, "%s%d", "lttng-", session_count) < 0) {
                        goto error;
                }
        }

        /* UUID generation */
        uuid_generate(new_session->uuid);
        uuid_copy(*session_id, new_session->uuid);

        /* Set consumer (identifier) to 0. This means that there is
         * NO consumer attach to that session yet.
         */
        new_session->ust_consumer = 0;
        new_session->lttng_consumer = 0;

        /* Init list */
        CDS_INIT_LIST_HEAD(&new_session->ust_traces);
        CDS_INIT_LIST_HEAD(&new_session->lttng_traces);

        /* Add new session to the global session list */
        add_session_list(new_session);

        return 0;

error:
        return -1;
}

/*
 *  ust_create_trace
 *
 *  Create an userspace trace using pid.
 *  This trace is then appended to the current session
 *  ust trace list.
 */
static int ust_create_trace(pid_t pid)
{
        int sock, ret;
        struct ltt_ust_trace *trace;

        trace = malloc(sizeof(struct ltt_ust_trace));
        if (trace == NULL) {
                perror("malloc");
                ret = -1;
                goto error;
        }

        /* Init */
        trace->pid = pid;
        trace->shmid = 0;

        /* Connect to app using ustctl API */
        sock = connect_app(pid);
        if (sock < 0) {
                ret = LTTCOMM_NO_TRACEABLE;
                goto error;
        }

        ret = ustctl_create_trace(sock, "auto");
        if (ret < 0) {
                ret = LTTCOMM_CREATE_FAIL;
                goto error;
        }

        /* Check if current session is valid */
        if (current_session) {
                cds_list_add(&trace->list, &current_session->ust_traces);
        }

error:
        return ret;
}

/*
 *      get_list_apps
 *
 *  List traceable user-space application and fill an
 *  array of pids.
 */
static void get_list_apps(pid_t *pids)
{
        int i = 0;
        struct ltt_traceable_app *iter;

        /* Protected by a mutex here because the threads manage_client
         * and manage_apps can access this list.
         */
        pthread_mutex_lock(&ltt_traceable_app_list_mutex);
        cds_list_for_each_entry(iter, &ltt_traceable_app_list.head, list) {
                pids[i] = iter->pid;
                i++;
        }
        pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
}

/*
 *  get_list_sessions
 *
 *  List sessions and fill the data buffer.
 */
static void get_list_sessions(struct lttng_session *lt)
{
        int i = 0;
        struct ltt_session *iter;
        struct lttng_session lsess;

        /* Iterate over session list and append data after
         * the control struct in the buffer.
         */
        cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
                /* Copy name and uuid */
                uuid_unparse(iter->uuid, lsess.uuid);
                strncpy(lsess.name, iter->name, sizeof(lsess.name));
                lsess.name[sizeof(lsess.name) - 1] = '\0';
                memcpy(&lt[i], &lsess, sizeof(lsess));
                i++;
                /* Reset struct for next pass */
                memset(&lsess, 0, sizeof(lsess));
        }
}

/*
 *  copy_common_data
 *
 *  Copy common data between lttcomm_lttng_msg and lttcomm_session_msg
 */
static void copy_common_data(struct lttcomm_lttng_msg *llm, struct lttcomm_session_msg *lsm)
{
        llm->cmd_type = lsm->cmd_type;
        llm->pid = lsm->pid;

        /* Manage uuid */
        if (!uuid_is_null(lsm->session_id)) {
                uuid_copy(llm->session_id, lsm->session_id);
        }

        strncpy(llm->trace_name, lsm->trace_name, strlen(llm->trace_name));
        llm->trace_name[strlen(llm->trace_name) - 1] = '\0';
}

/*
 *  setup_data_buffer
 *
 *  Setup the outgoing data buffer for the response
 *  data allocating the right amount of memory.
 *
 *  Return total size of the buffer pointed by buf.
 */
static int setup_data_buffer(char **buf, size_t s_data, struct lttcomm_lttng_msg *llm)
{
        int ret = 0;
        size_t buf_size;

        buf_size = sizeof(struct lttcomm_lttng_msg) + s_data;
        *buf = malloc(buf_size);
        if (*buf == NULL) {
                perror("malloc");
                ret = -1;
                goto error;
        }

        /* Setup lttcomm_lttng_msg data and copy
         * it to the newly allocated buffer.
         */
        llm->size_payload = s_data;
        memcpy(*buf, llm, sizeof(struct lttcomm_lttng_msg));

        return buf_size;

error:
        return ret;
}

/*
 *      process_client_msg
 *
 *      This takes the lttcomm_session_msg struct and process the command requested
 *      by the client. It then creates response(s) and send it back to the
 *      given socket (sock).
 *
 *      Return any error encountered or 0 for success.
 */
static int process_client_msg(int sock, struct lttcomm_session_msg *lsm)
{
        int ret;
        int buf_size;
        char *send_buf = NULL;
        struct lttcomm_lttng_msg llm;

        /* Copy common data to identify the response
         * on the lttng client side.
         */
        copy_common_data(&llm, lsm);

        /* Check command that needs a session */
        if (lsm->cmd_type != LTTNG_CREATE_SESSION &&
                lsm->cmd_type != LTTNG_LIST_SESSIONS &&
                lsm->cmd_type != UST_LIST_APPS)
        {
                current_session = find_session_by_uuid(lsm->session_id);
                if (current_session == NULL) {
                        ret = LTTCOMM_SELECT_SESS;
                        goto end;
                }
        }


        /* Default return code.
         * In our world, everything is OK... right? ;)
         */
        llm.ret_code = LTTCOMM_OK;

        /* Process by command type */
        switch (lsm->cmd_type) {
                case LTTNG_CREATE_SESSION:
                {
                        ret = create_session(lsm->session_name, &llm.session_id);
                        if (ret < 0) {
                                goto end;
                        }

                        buf_size = setup_data_buffer(&send_buf, 0, &llm);
                        if (buf_size < 0) {
                                ret = LTTCOMM_FATAL;
                                goto end;
                        }

                        break;
                }
                case LTTNG_DESTROY_SESSION:
                {
                        ret = destroy_session(&lsm->session_id);
                        if (ret < 0) {
                                ret = LTTCOMM_NO_SESS;
                        } else {
                                ret = LTTCOMM_OK;
                        }

                        /* No auxiliary data so only send the llm struct. */
                        goto end;
                }
                case UST_CREATE_TRACE:
                {
                        ret = ust_create_trace(lsm->pid);
                        if (ret < 0) {
                                ret = LTTCOMM_CREATE_FAIL;
                                goto end;
                        }

                        /* No auxiliary data so only send the llm struct. */
                        goto end;
                }
                case UST_LIST_APPS:
                {
                        /* Stop right now if no apps */
                        if (traceable_app_count == 0) {
                                ret = LTTCOMM_NO_APPS;
                                goto end;
                        }

                        /* Setup data buffer and details for transmission */
                        buf_size = setup_data_buffer(&send_buf,
                                        sizeof(pid_t) * traceable_app_count, &llm);
                        if (buf_size < 0) {
                                ret = LTTCOMM_FATAL;
                                goto end;
                        }

                        get_list_apps((pid_t *)(send_buf + sizeof(struct lttcomm_lttng_msg)));

                        break;
                }
                case LTTNG_LIST_SESSIONS:
                {
                        /* Stop right now if no session */
                        if (session_count == 0) {
                                ret = LTTCOMM_NO_SESS;
                                goto end;
                        }

                        /* Setup data buffer and details for transmission */
                        buf_size = setup_data_buffer(&send_buf,
                                        (sizeof(struct lttng_session) * session_count), &llm);
                        if (buf_size < 0) {
                                ret = LTTCOMM_FATAL;
                                goto end;
                        }

                        get_list_sessions((struct lttng_session *)(send_buf + sizeof(struct lttcomm_lttng_msg)));

                        break;
                }
                default:
                {
                        /* Undefined command */
                        ret = LTTCOMM_UND;
                        goto end;
                }
        }

        ret = send_unix_sock(sock, send_buf, buf_size);

        if (send_buf != NULL) {
                free(send_buf);
        }

        return ret;

end:
        /* Notify client of error */
        llm.ret_code = ret;
        llm.size_payload = 0;
        send_unix_sock(sock, (void*) &llm, sizeof(llm));

        return ret;
}

/*
 * usage function on stderr
 */
static void usage(void)
{
        fprintf(stderr, "Usage:\n%s OPTIONS\n\nOptions:\n"
                        "\t-h, --help\t\tDisplay this usage.\n"
                        "\t-c, --client-sock PATH\t\tSpecify path for the client unix socket\n"
                        "\t-a, --apps-sock PATH\t\tSpecify path for apps unix socket.\n"
                        "\t-d, --daemonize\t\tStart as a daemon.\n"
                        "\t-g, --group NAME\t\tSpecify the tracing group name. (default: tracing)\n"
                        "\t-V, --version\t\tShow version number.\n"
                        "\t-S, --sig-parent\t\tSend SIGCHLD to parent pid to notify readiness.\n"
                        "\t-q, --quiet\t\tNo output at all.\n",
                        progname);
}

/*
 * daemon argument parsing
 */
static int parse_args(int argc, char **argv)
{
        int c;

        static struct option long_options[] = {
                { "client-sock", 1, 0, 'c' },
                { "apps-sock", 1, 0, 'a' },
                { "daemonize", 0, 0, 'd' },
                { "sig-parent", 0, 0, 'S' },
                { "help", 0, 0, 'h' },
                { "group", 1, 0, 'g' },
                { "version", 0, 0, 'V' },
                { "quiet", 0, 0, 'q' },
                { NULL, 0, 0, 0 }
        };

        while (1) {
                int option_index = 0;
                c = getopt_long(argc, argv, "dhqVS" "a:c:g:s:", long_options, &option_index);
                if (c == -1) {
                        break;
                }

                switch (c) {
                case 0:
                        fprintf(stderr, "option %s", long_options[option_index].name);
                        if (optarg) {
                                fprintf(stderr, " with arg %s\n", optarg);
                        }
                        break;
                case 's':
                        snprintf(client_unix_sock_path, PATH_MAX, "%s", optarg);
                        break;
                case 'a':
                        snprintf(apps_unix_sock_path, PATH_MAX, "%s", optarg);
                        break;
                case 'd':
                        opt_daemon = 1;
                        break;
                case 'g':
                        opt_tracing_group = strdup(optarg);
                        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 'q':
                        opt_quiet = 1;
                        break;
                default:
                        /* Unknown option or other error.
                         * Error is printed by getopt, just return */
                        return -1;
                }
        }

        return 0;
}

/*
 *      init_daemon_socket
 *
 *      Creates the two needed socket by the daemon.
 *              apps_socket - The communication socket for all UST apps.
 *              client_socket - The communication of the cli tool (lttng).
 */
static int init_daemon_socket()
{
        int ret = 0;
        mode_t old_umask;

        old_umask = umask(0);

        /* Create client tool unix socket */
        client_socket = lttcomm_create_unix_sock(client_unix_sock_path);
        if (client_socket < 0) {
                ret = -1;
                goto end;
        }

        /* File permission MUST be 660 */
        ret = chmod(client_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
        if (ret < 0) {
                perror("chmod");
                goto end;
        }

        /* Create the application unix socket */
        apps_socket = lttcomm_create_unix_sock(apps_unix_sock_path);
        if (apps_socket < 0) {
                ret = -1;
                goto end;
        }

        /* File permission MUST be 660 */
        ret = chmod(apps_unix_sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
        if (ret < 0) {
                perror("chmod");
                goto end;
        }

end:
        umask(old_umask);
        return ret;
}

/*
 *      check_existing_daemon
 *
 *      Check if the global socket is available.
 *      If yes, error is returned.
 */
static int check_existing_daemon()
{
        int ret;

        ret = access(client_unix_sock_path, F_OK);
        if (ret == 0) {
                ret = access(apps_unix_sock_path, F_OK);
        }

        return ret;
}

/*
 *      get_home_dir
 *
 *      Return pointer to home directory path using
 *      the env variable HOME.
 *
 *      Default : /tmp
 */
static const char *get_home_dir(void)
{
        const char *home_path;

        if ((home_path = (const char *) getenv("HOME")) == NULL) {
                home_path = default_home_dir;
        }

        return home_path;
}

/*
 *  set_socket_perms
 *
 *      Set the tracing group gid onto the client socket.
 */
static int set_socket_perms(void)
{
        int ret;
        struct group *grp;

        /* Decide which group name to use */
        (opt_tracing_group != NULL) ?
                (grp = getgrnam(opt_tracing_group)) :
                (grp = getgrnam(default_tracing_group));

        if (grp == NULL) {
                ERR("Missing tracing group. Aborting execution.\n");
                ret = -1;
                goto end;
        }

        ret = chown(client_unix_sock_path, 0, grp->gr_gid);
        if (ret < 0) {
                perror("chown");
        }

end:
        return ret;
}

/*
 *      set_signal_handler
 *
 *      Setup signal handler for :
 *              SIGINT, SIGTERM, SIGPIPE
 */
static int set_signal_handler(void)
{
        int ret = 0;
        struct sigaction sa;
        sigset_t sigset;

        if ((ret = sigemptyset(&sigset)) < 0) {
                perror("sigemptyset");
                return ret;
        }

        sa.sa_handler = sighandler;
        sa.sa_mask = sigset;
        sa.sa_flags = 0;
        if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
                perror("sigaction");
                return ret;
        }

        if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) {
                perror("sigaction");
                return ret;
        }

        if ((ret = sigaction(SIGPIPE, &sa, NULL)) < 0) {
                perror("sigaction");
                return ret;
        }

        return ret;
}

/**
 *      sighandler
 *
 *      Signal handler for the daemon
 */
static void sighandler(int sig)
{
        switch (sig) {
                case SIGPIPE:
                        return;
                case SIGINT:
                case SIGTERM:
                        cleanup();
                        break;
                default:
                        break;
        }

        exit(EXIT_SUCCESS);
}

/*
 *      cleanup 
 *
 *      Cleanup the daemon on exit
 */
static void cleanup()
{
        /* <fun> */
        MSG("\n\n%c[%d;%dm*** assert failed *** ==> %c[%dm", 27,1,31,27,0);
        MSG("%c[%d;%dm Matthew, BEET driven development works!%c[%dm\n",27,1,33,27,0);
        /* </fun> */

        unlink(client_unix_sock_path);
        unlink(apps_unix_sock_path);
}

/*
 * main
 */
int main(int argc, char **argv)
{
        int i;
        int ret = 0;
        void *status;
        pthread_t threads[2];

        /* Parse arguments */
        progname = argv[0];
        if ((ret = parse_args(argc, argv) < 0)) {
                goto error;
        }

        /* Daemonize */
        if (opt_daemon) {
                ret = daemon(0, 0);
                if (ret < 0) {
                        perror("daemon");
                        goto error;
                }
        }

        /* Check if daemon is UID = 0 */
        is_root = !getuid();

        /* Set all sockets path */
        if (is_root) {
                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));
                }
        } else {
                if (strlen(apps_unix_sock_path) == 0) {
                        (snprintf(apps_unix_sock_path, PATH_MAX,
                                        DEFAULT_HOME_APPS_UNIX_SOCK, get_home_dir()));
                }

                /* 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, get_home_dir()));
                }
        }

        /* See if daemon already exist. If any of the two
         * socket needed by the daemon are present, this test fails
         */
        if ((ret = check_existing_daemon()) == 0) {
                ERR("Already running daemon.\n");
                goto error;
        }

        if (set_signal_handler() < 0) {
                goto error;
        }

        /* Setup the two needed unix socket */
        if (init_daemon_socket() < 0) {
                goto error;
        }

        /* Set credentials to socket */
        if (is_root && (set_socket_perms() < 0)) {
                goto error;
        }

        /* Get parent pid if -S, --sig-parent is specified. */
        if (opt_sig_parent) {
                ppid = getppid();
        }

        while (1) {
                /* Create thread to manage the client socket */
                ret = pthread_create(&threads[0], NULL, thread_manage_clients, (void *) NULL);
                if (ret != 0) {
                        perror("pthread_create");
                        goto error;
                }

                /* Create thread to manage application socket */
                ret = pthread_create(&threads[1], NULL, thread_manage_apps, (void *) NULL);
                if (ret != 0) {
                        perror("pthread_create");
                        goto error;
                }

                for (i = 0; i < 2; i++) {
                        ret = pthread_join(threads[i], &status);
                        if (ret != 0) {
                                perror("pthread_join");
                                goto error;
                        }
                }
        }

        cleanup();
        return 0;

error:
        cleanup();

        return EXIT_FAILURE;
}