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 struct ltt_session_list ltt_session_list = {
  37         .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
  38 };
  39
  40 /*
  41  *  get_session_list
  42  *
  43  *  Return a pointer to the session list.
  44  */
  45 struct ltt_session_list *get_session_list(void)
  46 {
  47         return &ltt_session_list;
  48 }
  49
  50 /*
  51  *  get_session_count
  52  *
  53  *  Return session_count
  54  */
  55 unsigned int get_session_count(void)
  56 {
  57         return session_count;
  58 }
  59
  60 /*
  61  *  add_session_list
  62  *
  63  *  Add a ltt_session structure to the global list.
  64  */
  65 static void add_session_list(struct ltt_session *ls)
  66 {
  67         cds_list_add(&ls->list, &ltt_session_list.head);
  68         session_count++;
  69 }
  70
  71 /*
  72  *  del_session_list
  73  *
  74  *  Delete a ltt_session structure to the global list.
  75  */
  76 static void del_session_list(struct ltt_session *ls)
  77 {
  78         cds_list_del(&ls->list);
  79         /* Sanity check */
  80         if (session_count != 0) {
  81                 session_count--;
  82         }
  83 }
  84
  85 /*
  86  *      find_session_by_uuid
  87  *
  88  *      Return a ltt_session structure ptr that matches the uuid.
  89  */
  90 struct ltt_session *find_session_by_uuid(uuid_t session_id)
  91 {
  92         int found = 0;
  93         struct ltt_session *iter;
  94
  95         /* Sanity check for NULL session_id */
  96         if (uuid_is_null(session_id)) {
  97                 goto end;
  98         }
  99
 100         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 101                 if (uuid_compare(iter->uuid, session_id) == 0) {
 102                         found = 1;
 103                         break;
 104                 }
 105         }
 106
 107 end:
 108         if (!found) {
 109                 iter = NULL;
 110         }
 111         return iter;
 112 }
 113
 114 /*
 115  *      find_session_by_name
 116  *
 117  *      Return a ltt_session structure ptr that matches name.
 118  *      If no session found, NULL is returned.
 119  */
 120 struct ltt_session *find_session_by_name(char *name)
 121 {
 122         int found = 0;
 123         struct ltt_session *iter;
 124
 125         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 126                 if (strncmp(iter->name, name, strlen(name)) == 0) {
 127                         found = 1;
 128                         break;
 129                 }
 130         }
 131
 132         if (!found) {
 133                 iter = NULL;
 134         }
 135
 136         return iter;
 137 }
 138
 139 /*
 140  *      destroy_session
 141  *
 142  *  Delete session from the global session list
 143  *  and free the memory.
 144  *
 145  *  Return -1 if no session is found.
 146  *  On success, return 1;
 147  */
 148 int destroy_session(uuid_t *uuid)
 149 {
 150         int found = -1;
 151         struct ltt_session *iter;
 152
 153         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 154                 if (uuid_compare(iter->uuid, *uuid) == 0) {
 155                         DBG("Destroying session %s", iter->name);
 156                         del_session_list(iter);
 157                         free(iter);
 158                         found = 1;
 159                         break;
 160                 }
 161         }
 162
 163         return found;
 164 }
 165
 166 /*
 167  *      create_session
 168  *
 169  *      Create a brand new session and add it to the
 170  *      global session list.
 171  */
 172 int create_session(char *name, uuid_t *session_id)
 173 {
 174         struct ltt_session *new_session;
 175
 176         DBG("Creating session %s", name);
 177
 178         new_session = find_session_by_name(name);
 179         if (new_session != NULL) {
 180                 goto error;
 181         }
 182
 183         /* Allocate session data structure */
 184         new_session = malloc(sizeof(struct ltt_session));
 185         if (new_session == NULL) {
 186                 perror("malloc");
 187                 goto error_mem;
 188         }
 189
 190         if (name != NULL) {
 191                 if (asprintf(&new_session->name, "%s", name) < 0) {
 192                         goto error_mem;
 193                 }
 194         } else {
 195                 /* Generate session name based on the session count */
 196                 if (asprintf(&new_session->name, "%s%d", "lttng-", session_count) < 0) {
 197                         goto error_mem;
 198                 }
 199         }
 200
 201         /* UUID generation */
 202         uuid_generate(new_session->uuid);
 203         uuid_copy(*session_id, new_session->uuid);
 204
 205         /* Set consumer (identifier) to 0. This means that there is
 206          * NO consumer attach to that session yet.
 207          */
 208         new_session->ust_consumer = 0;
 209         new_session->kernel_consumer = 0;
 210
 211         /* Init list */
 212         CDS_INIT_LIST_HEAD(&new_session->ust_traces);
 213
 214         /* Set trace list counter */
 215         new_session->ust_trace_count = 0;
 216
 217         /* Add new session to the global session list */
 218         add_session_list(new_session);
 219
 220         return 0;
 221
 222 error:
 223         return -1;
 224
 225 error_mem:
 226         return -ENOMEM;
 227 }
 228
 229 /*
 230  *  get_lttng_session
 231  *
 232  *  Iterate over the global session list and
 233  *  fill the lttng_session array.
 234  */
 235 void get_lttng_session(struct lttng_session *sessions)
 236 {
 237         int i = 0;
 238         struct ltt_session *iter;
 239         struct lttng_session lsess;
 240
 241         DBG("Getting all available session");
 242
 243         /* Iterate over session list and append data after
 244          * the control struct in the buffer.
 245          */
 246         cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
 247                 /* Copy name and uuid */
 248                 uuid_copy(lsess.uuid, iter->uuid);
 249                 strncpy(lsess.name, iter->name, sizeof(lsess.name));
 250                 lsess.name[sizeof(lsess.name) - 1] = '\0';
 251                 memcpy(&sessions[i], &lsess, sizeof(lsess));
 252                 i++;
 253                 /* Reset struct for next pass */
 254                 memset(&lsess, 0, sizeof(lsess));
 255         }
 256 }
 257