ltt-sessiond/session.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <lttng/liblttngctl.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <urcu/list.h>
  25 #include <uuid/uuid.h>
  26
  27 #include "lttngerr.h"
  28 #include "session.h"
  29
  30 /* Variables */
  31 static unsigned int session_count;
  32
  33 /* Static internal function */
  34 static void add_session_list(struct ltt_session *ls);
  35 static void del_session_list(struct ltt_session *ls);
  36
  37 /* Init session's list */
  38 static struct ltt_session_list ltt_session_list = {
  39         .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
  40 };
  41
  42 /*
  43  *  get_session_count
  44  *
  45  *  Return session_count
  46  */
  47 unsigned int get_session_count(void)
  48 {
  49         return session_count;
  50 }
  51
  52 /*
  53  *  add_session_list
  54  *
  55  *  Add a ltt_session structure to the global list.
  56  */
  57 static void add_session_list(struct ltt_session *ls)
  58 {
  59         cds_list_add(&ls->list, &ltt_session_list.head);
  60         session_count++;
  61 }
  62
  63 /*
  64  *  del_session_list
  65  *
  66  *  Delete a ltt_session structure to the global list.
  67  */
  68 static void del_session_list(struct ltt_session *ls)
  69 {
  70         cds_list_del(&ls->list);
  71         /* Sanity check */
  72         if (session_count != 0) {
  73                 session_count--;
  74         }
  75 }
  76
  77 /*
  78  *      find_session_by_uuid
  79  *
  80  *      Return a ltt_session structure ptr that matches the uuid.
  81  */
  82 struct ltt_session *find_session_by_uuid(uuid_t session_id)
  83 {
  84         int found = 0;
  85         struct ltt_session *iter;
  86
  87         /* Sanity check for NULL session_id */
  88         if (uuid_is_null(session_id)) {
  89                 goto end;
  90         }
  91
  92         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
  93                 if (uuid_compare(iter->uuid, session_id) == 0) {
  94                         found = 1;
  95                         break;
  96                 }
  97         }
  98
  99 end:
 100         if (!found) {
 101                 iter = NULL;
 102         }
 103         return iter;
 104 }
 105
 106 /*
 107  *      find_session_by_name
 108  *
 109  *      Return a ltt_session structure ptr that matches name.
 110  *      If no session found, NULL is returned.
 111  */
 112 struct ltt_session *find_session_by_name(char *name)
 113 {
 114         int found = 0;
 115         struct ltt_session *iter;
 116
 117         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 118                 if (strncmp(iter->name, name, strlen(iter->name)) == 0) {
 119                         found = 1;
 120                         break;
 121                 }
 122         }
 123
 124         if (!found) {
 125                 iter = NULL;
 126         }
 127
 128         return iter;
 129 }
 130
 131 /*
 132  *      destroy_session
 133  *
 134  *  Delete session from the global session list
 135  *  and free the memory.
 136  *
 137  *  Return -1 if no session is found.
 138  *  On success, return 1;
 139  */
 140 int destroy_session(uuid_t *uuid)
 141 {
 142         int found = -1;
 143         struct ltt_session *iter;
 144
 145         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 146                 if (uuid_compare(iter->uuid, *uuid) == 0) {
 147                         del_session_list(iter);
 148                         free(iter);
 149                         found = 1;
 150                         break;
 151                 }
 152         }
 153
 154         return found;
 155 }
 156
 157 /*
 158  *      create_session
 159  *
 160  *      Create a brand new session and add it to the
 161  *      global session list.
 162  */
 163 int create_session(char *name, uuid_t *session_id)
 164 {
 165         struct ltt_session *new_session;
 166
 167         new_session = find_session_by_name(name);
 168         if (new_session != NULL) {
 169                 goto error;
 170         }
 171
 172         /* Allocate session data structure */
 173         new_session = malloc(sizeof(struct ltt_session));
 174         if (new_session == NULL) {
 175                 perror("malloc");
 176                 goto error_mem;
 177         }
 178
 179         if (name != NULL) {
 180                 if (asprintf(&new_session->name, "%s", name) < 0) {
 181                         goto error_mem;
 182                 }
 183         } else {
 184                 /* Generate session name based on the session count */
 185                 if (asprintf(&new_session->name, "%s%d", "lttng-", session_count) < 0) {
 186                         goto error_mem;
 187                 }
 188         }
 189
 190         /* UUID generation */
 191         uuid_generate(new_session->uuid);
 192         uuid_copy(*session_id, new_session->uuid);
 193
 194         /* Set consumer (identifier) to 0. This means that there is
 195          * NO consumer attach to that session yet.
 196          */
 197         new_session->ust_consumer = 0;
 198         new_session->lttng_consumer = 0;
 199
 200         /* Init list */
 201         CDS_INIT_LIST_HEAD(&new_session->ust_traces);
 202         CDS_INIT_LIST_HEAD(&new_session->lttng_traces);
 203
 204         /* Add new session to the global session list */
 205         add_session_list(new_session);
 206
 207         return 0;
 208
 209 error:
 210         return -1;
 211
 212 error_mem:
 213         return -ENOMEM;
 214 }
 215
 216 /*
 217  *  get_lttng_session
 218  *
 219  *  Iterate over the global session list and
 220  *  fill the lttng_session array.
 221  */
 222 void get_lttng_session(struct lttng_session *lt)
 223 {
 224         int i = 0;
 225         struct ltt_session *iter;
 226         struct lttng_session lsess;
 227
 228         /* Iterate over session list and append data after
 229          * the control struct in the buffer.
 230          */
 231         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 232                 /* Copy name and uuid */
 233                 uuid_unparse(iter->uuid, lsess.uuid);
 234                 strncpy(lsess.name, iter->name, sizeof(lsess.name));
 235                 lsess.name[sizeof(lsess.name) - 1] = '\0';
 236                 memcpy(&lt[i], &lsess, sizeof(lsess));
 237                 i++;
 238                 /* Reset struct for next pass */
 239                 memset(&lsess, 0, sizeof(lsess));
 240         }
 241 }
 242