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 <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <urcu/list.h>
  24
  25 #include "lttngerr.h"
  26 #include "session.h"
  27
  28 /* Variables */
  29 static unsigned int session_count;
  30
  31 /* Static internal function */
  32 static void add_session_list(struct ltt_session *ls);
  33 static void del_session_list(struct ltt_session *ls);
  34
  35 /* Init session's list */
  36 static struct ltt_session_list ltt_session_list = {
  37         .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
  38 };
  39
  40 /*
  41  *  get_session_count
  42  *
  43  *  Return session_count
  44  */
  45 unsigned int get_session_count(void)
  46 {
  47         return session_count;
  48 }
  49
  50 /*
  51  *  add_session_list
  52  *
  53  *  Add a ltt_session structure to the global list.
  54  */
  55 static void add_session_list(struct ltt_session *ls)
  56 {
  57         cds_list_add(&ls->list, &ltt_session_list.head);
  58         session_count++;
  59 }
  60
  61 /*
  62  *  del_session_list
  63  *
  64  *  Delete a ltt_session structure to the global list.
  65  */
  66 static void del_session_list(struct ltt_session *ls)
  67 {
  68         cds_list_del(&ls->list);
  69         /* Sanity check */
  70         if (session_count != 0) {
  71                 session_count--;
  72         }
  73 }
  74
  75 /*
  76  *      find_session_by_uuid
  77  *
  78  *      Return a ltt_session structure ptr that matches the uuid.
  79  */
  80 struct ltt_session *find_session_by_uuid(uuid_t session_id)
  81 {
  82         int found = 0;
  83         struct ltt_session *iter;
  84
  85         /* Sanity check for NULL session_id */
  86         if (uuid_is_null(session_id)) {
  87                 goto end;
  88         }
  89
  90         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
  91                 if (uuid_compare(iter->uuid, session_id) == 0) {
  92                         found = 1;
  93                         break;
  94                 }
  95         }
  96
  97 end:
  98         if (!found) {
  99                 iter = NULL;
 100         }
 101         return iter;
 102 }
 103
 104 /*
 105  *      find_session_by_name
 106  *
 107  *      Return a ltt_session structure ptr that matches name.
 108  *      If no session found, NULL is returned.
 109  */
 110 struct ltt_session *find_session_by_name(char *name)
 111 {
 112         int found = 0;
 113         struct ltt_session *iter;
 114
 115         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 116                 if (strncmp(iter->name, name, strlen(name)) == 0) {
 117                         found = 1;
 118                         break;
 119                 }
 120         }
 121
 122         if (!found) {
 123                 iter = NULL;
 124         }
 125
 126         return iter;
 127 }
 128
 129 /*
 130  *      destroy_session
 131  *
 132  *  Delete session from the global session list
 133  *  and free the memory.
 134  *
 135  *  Return -1 if no session is found.
 136  *  On success, return 1;
 137  */
 138 int destroy_session(uuid_t *uuid)
 139 {
 140         int found = -1;
 141         struct ltt_session *iter;
 142
 143         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 144                 if (uuid_compare(iter->uuid, *uuid) == 0) {
 145                         DBG("Destroying session %s", iter->name);
 146                         del_session_list(iter);
 147                         free(iter);
 148                         found = 1;
 149                         break;
 150                 }
 151         }
 152
 153         return found;
 154 }
 155
 156 /*
 157  *      create_session
 158  *
 159  *      Create a brand new session and add it to the
 160  *      global session list.
 161  */
 162 int create_session(char *name, uuid_t *session_id)
 163 {
 164         struct ltt_session *new_session;
 165
 166         DBG("Creating session %s", name);
 167
 168         new_session = find_session_by_name(name);
 169         if (new_session != NULL) {
 170                 goto error;
 171         }
 172
 173         /* Allocate session data structure */
 174         new_session = malloc(sizeof(struct ltt_session));
 175         if (new_session == NULL) {
 176                 perror("malloc");
 177                 goto error_mem;
 178         }
 179
 180         if (name != NULL) {
 181                 if (asprintf(&new_session->name, "%s", name) < 0) {
 182                         goto error_mem;
 183                 }
 184         } else {
 185                 /* Generate session name based on the session count */
 186                 if (asprintf(&new_session->name, "%s%d", "lttng-", session_count) < 0) {
 187                         goto error_mem;
 188                 }
 189         }
 190
 191         /* UUID generation */
 192         uuid_generate(new_session->uuid);
 193         uuid_copy(*session_id, new_session->uuid);
 194
 195         /* Set consumer (identifier) to 0. This means that there is
 196          * NO consumer attach to that session yet.
 197          */
 198         new_session->ust_consumer = 0;
 199         new_session->kernel_consumer = 0;
 200
 201         /* Init list */
 202         CDS_INIT_LIST_HEAD(&new_session->ust_traces);
 203         CDS_INIT_LIST_HEAD(&new_session->kernel_traces);
 204
 205         /* Set trace list counter */
 206         new_session->ust_trace_count = 0;
 207         new_session->kern_trace_count = 0;
 208
 209         /* Add new session to the global session list */
 210         add_session_list(new_session);
 211
 212         return 0;
 213
 214 error:
 215         return -1;
 216
 217 error_mem:
 218         return -ENOMEM;
 219 }
 220
 221 /*
 222  *  get_lttng_session
 223  *
 224  *  Iterate over the global session list and
 225  *  fill the lttng_session array.
 226  */
 227 void get_lttng_session(struct lttng_session *sessions)
 228 {
 229         int i = 0;
 230         struct ltt_session *iter;
 231         struct lttng_session lsess;
 232
 233         DBG("Getting all available session");
 234
 235         /* Iterate over session list and append data after
 236          * the control struct in the buffer.
 237          */
 238         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 239                 /* Copy name and uuid */
 240                 uuid_copy(lsess.uuid, iter->uuid);
 241                 strncpy(lsess.name, iter->name, sizeof(lsess.name));
 242                 lsess.name[sizeof(lsess.name) - 1] = '\0';
 243                 memcpy(&sessions[i], &lsess, sizeof(lsess));
 244                 i++;
 245                 /* Reset struct for next pass */
 246                 memset(&lsess, 0, sizeof(lsess));
 247         }
 248 }
 249