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