include/lttng/notification/notification-internal.h

   1 /*
   2  * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This library is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18 #ifndef LTTNG_NOTIFICATION_INTERNAL_H
  19 #define LTTNG_NOTIFICATION_INTERNAL_H
  20
  21 #include <lttng/notification/notification.h>
  22 #include <common/macros.h>
  23 #include <common/buffer-view.h>
  24 #include <stdint.h>
  25 #include <stdbool.h>
  26 #include <sys/types.h>
  27
  28 struct lttng_notification {
  29         struct lttng_condition *condition;
  30         struct lttng_evaluation *evaluation;
  31         /*
  32          * The ownership of the notification's inner-elements depends
  33          * on the way it was created. The notification owns both
  34          * the condition and evaluation if it was obtained from a notification
  35          * channel (i.e. created using lttng_notification_create_from_buffer)
  36          * as the user may never access the condition and evaluation,
  37          * thus never getting a chance to free them.
  38          *
  39          * However, when the _private_ lttng_notification_create() function
  40          * is used, no ownership of condition and evaluation is assumed by
  41          * the notification object. The main reason for this change in
  42          * behavior is that internal users of this API only use the object
  43          * to use its serialization facilities.
  44          */
  45         bool owns_elements;
  46 };
  47
  48 struct lttng_notification_comm {
  49         /* Size of the payload following this field. */
  50         uint32_t length;
  51         /* Condition and evaluation objects follow. */
  52         char payload[];
  53 } LTTNG_PACKED;
  54
  55 LTTNG_HIDDEN
  56 struct lttng_notification *lttng_notification_create(
  57                 struct lttng_condition *condition,
  58                 struct lttng_evaluation *evaluation);
  59
  60 LTTNG_HIDDEN
  61 ssize_t lttng_notification_serialize(struct lttng_notification *notification,
  62                 char *buf);
  63
  64 LTTNG_HIDDEN
  65 ssize_t lttng_notification_create_from_buffer(
  66                 const struct lttng_buffer_view *view,
  67                 struct lttng_notification **notification);
  68
  69 #endif /* LTTNG_NOTIFICATION_INTERNAL_H */