src/bin/lttng-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 modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef _LTT_SESSION_H
  19 #define _LTT_SESSION_H
  20
  21 #include <urcu/list.h>
  22
  23 #include "trace-kernel.h"
  24
  25 struct ltt_ust_session;
  26
  27 /*
  28  * Tracing session list
  29  *
  30  * Statically declared in session.c and can be accessed by using
  31  * session_get_list() function that returns the pointer to the list.
  32  */
  33 struct ltt_session_list {
  34         /*
  35          * This lock protects any read/write access to the list and
  36          * next_uuid. All public functions in session.c acquire this
  37          * lock and release it before returning. If none of those
  38          * functions are used, the lock MUST be acquired in order to
  39          * iterate or/and do any actions on that list.
  40          */
  41         pthread_mutex_t lock;
  42
  43         /*
  44          * Session unique ID generator. The session list lock MUST be
  45          * upon update and read of this counter.
  46          */
  47         unsigned int next_uuid;
  48
  49         /* Linked list head */
  50         struct cds_list_head head;
  51 };
  52
  53 /*
  54  * This data structure contains information needed to identify a tracing
  55  * session for both LTTng and UST.
  56  */
  57 struct ltt_session {
  58         char name[NAME_MAX];
  59         char path[PATH_MAX];
  60         struct ltt_kernel_session *kernel_session;
  61         struct ltt_ust_session *ust_session;
  62         /*
  63          * Protect any read/write on this session data structure. This lock must be
  64          * acquired *before* using any public functions declared below. Use
  65          * session_lock() and session_unlock() for that.
  66          */
  67         pthread_mutex_t lock;
  68         struct cds_list_head list;
  69         int enabled;    /* enabled/started flag */
  70         unsigned int id;                /* session unique identifier */
  71         /* UID/GID of the user owning the session */
  72         uid_t uid;
  73         gid_t gid;
  74         /*
  75          * Network session handle. A value of 0 means that there is no remote
  76          * session established.
  77          */
  78         uint64_t net_handle;
  79         /*
  80          * This consumer is only set when the create_session_uri call is made.
  81          * This contains the temporary information for a consumer output. Upon
  82          * creation of the UST or kernel session, this consumer, if available, is
  83          * copied into those sessions.
  84          */
  85         struct consumer_output *consumer;
  86
  87         /* Did a start command occured before the kern/ust session creation? */
  88         unsigned int started;
  89 };
  90
  91 /* Prototypes */
  92 int session_create(char *name, char *path, uid_t uid, gid_t gid);
  93 int session_destroy(struct ltt_session *session);
  94
  95 void session_lock(struct ltt_session *session);
  96 void session_lock_list(void);
  97 void session_unlock(struct ltt_session *session);
  98 void session_unlock_list(void);
  99
 100 struct ltt_session *session_find_by_name(char *name);
 101 struct ltt_session_list *session_get_list(void);
 102
 103 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
 104
 105 #endif /* _LTT_SESSION_H */