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 #include "trace-ust.h"
  25
  26 /*
  27  * Tracing session list
  28  *
  29  * Statically declared in session.c and can be accessed by using
  30  * session_get_list() function that returns the pointer to the list.
  31  */
  32 struct ltt_session_list {
  33         /*
  34          * This lock protects any read/write access to the list and
  35          * next_uuid. All public functions in session.c acquire this
  36          * lock and release it before returning. If none of those
  37          * functions are used, the lock MUST be acquired in order to
  38          * iterate or/and do any actions on that list.
  39          */
  40         pthread_mutex_t lock;
  41
  42         /*
  43          * Session unique ID generator. The session list lock MUST be
  44          * upon update and read of this counter.
  45          */
  46         unsigned int next_uuid;
  47
  48         /* Linked list head */
  49         struct cds_list_head head;
  50 };
  51
  52 /*
  53  * This data structure contains information needed to identify a tracing
  54  * session for both LTTng and UST.
  55  */
  56 struct ltt_session {
  57         char name[NAME_MAX];
  58         char path[PATH_MAX];
  59         struct ltt_kernel_session *kernel_session;
  60         struct ltt_ust_session *ust_session;
  61         /*
  62          * Protect any read/write on this session data structure. This lock must be
  63          * acquired *before* using any public functions declared below. Use
  64          * session_lock() and session_unlock() for that.
  65          */
  66         pthread_mutex_t lock;
  67         struct cds_list_head list;
  68         int enabled;    /* enabled/started flag */
  69         unsigned int id;                /* session unique identifier */
  70         /* UID/GID of the user owning the session */
  71         uid_t uid;
  72         gid_t gid;
  73         /*
  74          * Network session handle. A value of 0 means that there is no remote
  75          * session established.
  76          */
  77         uint64_t net_handle;
  78         /*
  79          * This consumer is only set when the create_session_uri call is made.
  80          * This contains the temporary information for a consumer output. Upon
  81          * creation of the UST or kernel session, this consumer, if available, is
  82          * copied into those sessions.
  83          */
  84         struct consumer_output *consumer;
  85
  86         /* Indicates whether or not we have to spawn consumer(s) */
  87         unsigned int start_consumer;
  88
  89         /* Did a start command occured before the kern/ust session creation? */
  90         unsigned int started;
  91 };
  92
  93 /* Prototypes */
  94 int session_create(char *name, char *path, uid_t uid, gid_t gid);
  95 int session_destroy(struct ltt_session *session);
  96
  97 void session_lock(struct ltt_session *session);
  98 void session_lock_list(void);
  99 void session_unlock(struct ltt_session *session);
 100 void session_unlock_list(void);
 101
 102 struct ltt_session *session_find_by_name(char *name);
 103 struct ltt_session_list *session_get_list(void);
 104
 105 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
 106
 107 #endif /* _LTT_SESSION_H */