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