include/lttng/channel.h

   1 /*
   2  * Copyright (C) 2014 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_CHANNEL_H
   9 #define LTTNG_CHANNEL_H
  10
  11 #include <lttng/domain.h>
  12 #include <lttng/event.h>
  13 #include <lttng/lttng-export.h>
  14
  15 #include <stdint.h>
  16
  17 #ifdef __cplusplus
  18 extern "C" {
  19 #endif
  20
  21 /*
  22  * Tracer channel attributes. For both kernel and user-space.
  23  *
  24  * The structures should be initialized to zero before use.
  25  */
  26 #define LTTNG_CHANNEL_ATTR_PADDING1 LTTNG_SYMBOL_NAME_LEN + 12
  27 struct lttng_channel_attr {
  28         int overwrite; /* -1: session default, 1: overwrite, 0: discard */
  29         uint64_t subbuf_size; /* bytes, power of 2 */
  30         uint64_t num_subbuf; /* power of 2 */
  31         unsigned int switch_timer_interval; /* usec */
  32         unsigned int read_timer_interval; /* usec */
  33         enum lttng_event_output output; /* splice, mmap */
  34         /* LTTng 2.1 padding limit */
  35         uint64_t tracefile_size; /* bytes */
  36         uint64_t tracefile_count; /* number of tracefiles */
  37         /* LTTng 2.3 padding limit */
  38         unsigned int live_timer_interval; /* usec */
  39         /* LTTng 2.7 padding limit */
  40         uint32_t align_to_64;
  41         union {
  42                 uint64_t padding;
  43                 void *ptr;
  44         } extended;
  45
  46         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
  47 };
  48
  49 /*
  50  * Channel information structure. For both kernel and user-space.
  51  *
  52  * The structures should be initialized to zero before use.
  53  */
  54 #define LTTNG_CHANNEL_PADDING1 16
  55 struct lttng_channel {
  56         char name[LTTNG_SYMBOL_NAME_LEN];
  57         uint32_t enabled;
  58         struct lttng_channel_attr attr;
  59
  60         char padding[LTTNG_CHANNEL_PADDING1];
  61 };
  62
  63 /*
  64  */
  65 LTTNG_EXPORT extern struct lttng_channel *lttng_channel_create(struct lttng_domain *domain);
  66
  67 /*
  68  */
  69 LTTNG_EXPORT extern void lttng_channel_destroy(struct lttng_channel *channel);
  70
  71 /*
  72  * List the channel(s) of a session.
  73  *
  74  * The handle CAN NOT be NULL.
  75  *
  76  * Return the size (number of entries) of the "lttng_channel" array. Caller
  77  * must free channels. On error, a negative LTTng error code is returned.
  78  */
  79 LTTNG_EXPORT extern int lttng_list_channels(struct lttng_handle *handle,
  80                                             struct lttng_channel **channels);
  81
  82 /*
  83  * Create or enable a channel.
  84  *
  85  * The chan and handle params can not be NULL.
  86  *
  87  * Return 0 on success else a negative LTTng error code.
  88  */
  89 LTTNG_EXPORT extern int lttng_enable_channel(struct lttng_handle *handle,
  90                                              struct lttng_channel *chan);
  91
  92 /*
  93  * Disable channel.
  94  *
  95  * Name and handle CAN NOT be NULL.
  96  *
  97  * Return 0 on success else a negative LTTng error code.
  98  */
  99 LTTNG_EXPORT extern int lttng_disable_channel(struct lttng_handle *handle, const char *name);
 100
 101 /*
 102  * Set the default channel attributes for a specific domain and an allocated
 103  * lttng_channel_attr pointer.
 104  *
 105  * If one or both arguments are NULL, nothing happens.
 106  */
 107 LTTNG_EXPORT extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 108                                                         struct lttng_channel_attr *attr);
 109
 110 /*
 111  * Get the discarded event count of a specific LTTng channel.
 112  *
 113  * Returns 0 on success, or a negative LTTng error code on error.
 114  */
 115 LTTNG_EXPORT extern int lttng_channel_get_discarded_event_count(struct lttng_channel *chan,
 116                                                                 uint64_t *discarded_events);
 117
 118 /*
 119  * Get the lost packet count of a specific LTTng channel.
 120  *
 121  * Returns 0 on success, or a negative LTTng error code on error.
 122  */
 123 LTTNG_EXPORT extern int lttng_channel_get_lost_packet_count(struct lttng_channel *chan,
 124                                                             uint64_t *lost_packets);
 125
 126 LTTNG_EXPORT extern int lttng_channel_get_monitor_timer_interval(struct lttng_channel *chan,
 127                                                                  uint64_t *monitor_timer_interval);
 128
 129 LTTNG_EXPORT extern int lttng_channel_set_monitor_timer_interval(struct lttng_channel *chan,
 130                                                                  uint64_t monitor_timer_interval);
 131
 132 LTTNG_EXPORT extern int lttng_channel_get_blocking_timeout(struct lttng_channel *chan,
 133                                                            int64_t *blocking_timeout);
 134
 135 LTTNG_EXPORT extern int lttng_channel_set_blocking_timeout(struct lttng_channel *chan,
 136                                                            int64_t blocking_timeout);
 137
 138 #ifdef __cplusplus
 139 }
 140 #endif
 141
 142 #endif /* LTTNG_CHANNEL_H */