ltt-sessiond/session.h

   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; only version 2
   7  * of the License.
   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 #ifndef _LTT_SESSION_H
  20 #define _LTT_SESSION_H
  21
  22 #include <pthread.h>
  23 #include <urcu/list.h>
  24
  25 #include "trace-kernel.h"
  26 #include "trace-ust.h"
  27
  28 /*
  29  * Tracing session list
  30  *
  31  * Statically declared in session.c and can be accessed by using
  32  * get_session_list() function that returns the pointer to the list.
  33  */
  34 struct ltt_session_list {
  35         /*
  36          * This lock protects any read/write access to the list and count (which is
  37          * basically the list size). All public functions in session.c acquire this
  38          * lock and release it before returning. If none of those functions are
  39          * used, the lock MUST be acquired in order to iterate or/and do any
  40          * actions on that list.
  41          */
  42         pthread_mutex_t lock;
  43
  44         /*
  45          * Number of element in the list. The session list lock MUST be acquired if
  46          * this counter is used when iterating over the session list.
  47          */
  48         unsigned int count;
  49
  50         /* Linked list head */
  51         struct cds_list_head head;
  52 };
  53
  54 /*
  55  * This data structure contains information needed to identify a tracing
  56  * session for both LTTng and UST.
  57  */
  58 struct ltt_session {
  59         char *name;
  60         char *path;
  61         struct ltt_kernel_session *kernel_session;
  62         struct cds_list_head ust_traces;
  63         unsigned int ust_trace_count;
  64         /*
  65          * Protect any read/write on this session data structure. This lock must be
  66          * acquired *before* using any public functions declared below. Use
  67          * lock_session() and unlock_session() for that.
  68          */
  69         pthread_mutex_t lock;
  70         struct cds_list_head list;
  71 };
  72
  73 /* Prototypes */
  74 int create_session(char *name, char *path);
  75 int destroy_session(char *name);
  76
  77 void lock_session(struct ltt_session *session);
  78 void lock_session_list(void);
  79 void unlock_session(struct ltt_session *session);
  80 void unlock_session_list(void);
  81
  82 struct ltt_session *find_session_by_name(char *name);
  83 struct ltt_session_list *get_session_list(void);
  84
  85 #endif /* _LTT_SESSION_H */