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 #include <stdint.h>
  15
  16 #ifdef __cplusplus
  17 extern "C" {
  18 #endif
  19
  20 /*
  21  * Tracer channel attributes. For both kernel and user-space.
  22  *
  23  * The structures should be initialized to zero before use.
  24  */
  25 #define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 12
  26 struct lttng_channel_attr {
  27         int overwrite;                      /* -1: session default, 1: overwrite, 0: discard */
  28         uint64_t subbuf_size;               /* bytes, power of 2 */
  29         uint64_t num_subbuf;                /* power of 2 */
  30         unsigned int switch_timer_interval; /* usec */
  31         unsigned int read_timer_interval;   /* usec */
  32         enum lttng_event_output output;     /* splice, mmap */
  33         /* LTTng 2.1 padding limit */
  34         uint64_t tracefile_size;            /* bytes */
  35         uint64_t tracefile_count;           /* number of tracefiles */
  36         /* LTTng 2.3 padding limit */
  37         unsigned int live_timer_interval;   /* usec */
  38         /* LTTng 2.7 padding limit */
  39         uint32_t align_to_64;
  40         union {
  41                 uint64_t padding;
  42                 void *ptr;
  43         } extended;
  44
  45         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
  46 };
  47
  48 /*
  49  * Channel information structure. For both kernel and user-space.
  50  *
  51  * The structures should be initialized to zero before use.
  52  */
  53 #define LTTNG_CHANNEL_PADDING1             16
  54 struct lttng_channel {
  55         char name[LTTNG_SYMBOL_NAME_LEN];
  56         uint32_t enabled;
  57         struct lttng_channel_attr attr;
  58
  59         char padding[LTTNG_CHANNEL_PADDING1];
  60 };
  61
  62 /*
  63  */
  64 LTTNG_EXPORT extern struct lttng_channel *lttng_channel_create(struct lttng_domain *domain);
  65
  66 /*
  67  */
  68 LTTNG_EXPORT extern void lttng_channel_destroy(struct lttng_channel *channel);
  69
  70 /*
  71  * List the channel(s) of a session.
  72  *
  73  * The handle CAN NOT be NULL.
  74  *
  75  * Return the size (number of entries) of the "lttng_channel" array. Caller
  76  * must free channels. On error, a negative LTTng error code is returned.
  77  */
  78 LTTNG_EXPORT extern int lttng_list_channels(struct lttng_handle *handle,
  79                 struct lttng_channel **channels);
  80
  81 /*
  82  * Create or enable a channel.
  83  *
  84  * The chan and handle params can not be NULL.
  85  *
  86  * Return 0 on success else a negative LTTng error code.
  87  */
  88 LTTNG_EXPORT extern int lttng_enable_channel(struct lttng_handle *handle,
  89                 struct lttng_channel *chan);
  90
  91 /*
  92  * Disable channel.
  93  *
  94  * Name and handle CAN NOT be NULL.
  95  *
  96  * Return 0 on success else a negative LTTng error code.
  97  */
  98 LTTNG_EXPORT extern int lttng_disable_channel(struct lttng_handle *handle,
  99                 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 */