include/lttng/channel.h

   1 /*
   2  * Copyright (C) 2014 - David Goulet <dgoulet@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_CHANNEL_H
  19 #define LTTNG_CHANNEL_H
  20
  21 #include <lttng/domain.h>
  22 #include <lttng/event.h>
  23 #include <stdint.h>
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28
  29 /*
  30  * Tracer channel attributes. For both kernel and user-space.
  31  *
  32  * The structures should be initialized to zero before use.
  33  */
  34 #define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 12
  35 struct lttng_channel_attr {
  36         int overwrite;                      /* -1: session default, 1: overwrite, 0: discard */
  37         uint64_t subbuf_size;               /* bytes, power of 2 */
  38         uint64_t num_subbuf;                /* power of 2 */
  39         unsigned int switch_timer_interval; /* usec */
  40         unsigned int read_timer_interval;   /* usec */
  41         enum lttng_event_output output;     /* splice, mmap */
  42         /* LTTng 2.1 padding limit */
  43         uint64_t tracefile_size;            /* bytes */
  44         uint64_t tracefile_count;           /* number of tracefiles */
  45         /* LTTng 2.3 padding limit */
  46         unsigned int live_timer_interval;   /* usec */
  47         /* LTTng 2.7 padding limit */
  48         uint32_t align_to_64;
  49         union {
  50                 uint64_t padding;
  51                 void *ptr;
  52         } extended;
  53
  54         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
  55 };
  56
  57 /*
  58  * Channel information structure. For both kernel and user-space.
  59  *
  60  * The structures should be initialized to zero before use.
  61  */
  62 #define LTTNG_CHANNEL_PADDING1             16
  63 struct lttng_channel {
  64         char name[LTTNG_SYMBOL_NAME_LEN];
  65         uint32_t enabled;
  66         struct lttng_channel_attr attr;
  67
  68         char padding[LTTNG_CHANNEL_PADDING1];
  69 };
  70
  71 /*
  72  */
  73 extern struct lttng_channel *lttng_channel_create(struct lttng_domain *domain);
  74
  75 /*
  76  */
  77 extern void lttng_channel_destroy(struct lttng_channel *channel);
  78
  79 /*
  80  * List the channel(s) of a session.
  81  *
  82  * The handle CAN NOT be NULL.
  83  *
  84  * Return the size (number of entries) of the "lttng_channel" array. Caller
  85  * must free channels. On error, a negative LTTng error code is returned.
  86  */
  87 extern int lttng_list_channels(struct lttng_handle *handle,
  88                 struct lttng_channel **channels);
  89
  90 /*
  91  * Create or enable a channel.
  92  *
  93  * The chan and handle params can not be NULL.
  94  *
  95  * Return 0 on success else a negative LTTng error code.
  96  */
  97 extern int lttng_enable_channel(struct lttng_handle *handle,
  98                 struct lttng_channel *chan);
  99
 100 /*
 101  * Disable channel.
 102  *
 103  * Name and handle CAN NOT be NULL.
 104  *
 105  * Return 0 on success else a negative LTTng error code.
 106  */
 107 extern int lttng_disable_channel(struct lttng_handle *handle,
 108                 const char *name);
 109
 110 /*
 111  * Set the default channel attributes for a specific domain and an allocated
 112  * lttng_channel_attr pointer.
 113  *
 114  * If one or both arguments are NULL, nothing happens.
 115  */
 116 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 117                 struct lttng_channel_attr *attr);
 118
 119 /*
 120  * Get the discarded event count of a specific LTTng channel.
 121  *
 122  * Returns 0 on success, or a negative LTTng error code on error.
 123  */
 124 extern int lttng_channel_get_discarded_event_count(struct lttng_channel *chan,
 125                 uint64_t *discarded_events);
 126
 127 /*
 128  * Get the lost packet count of a specific LTTng channel.
 129  *
 130  * Returns 0 on success, or a negative LTTng error code on error.
 131  */
 132 extern int lttng_channel_get_lost_packet_count(struct lttng_channel *chan,
 133                 uint64_t *lost_packets);
 134
 135 extern int lttng_channel_get_monitor_timer_interval(struct lttng_channel *chan,
 136                 uint64_t *monitor_timer_interval);
 137
 138 extern int lttng_channel_set_monitor_timer_interval(struct lttng_channel *chan,
 139                 uint64_t monitor_timer_interval);
 140
 141 #ifdef __cplusplus
 142 }
 143 #endif
 144
 145 #endif /* LTTNG_CHANNEL_H */