src/common/trace-chunk-registry.h

   1 /*
   2  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_TRACE_CHUNK_REGISTRY_H
   9 #define LTTNG_TRACE_CHUNK_REGISTRY_H
  10
  11 #include <stddef.h>
  12 #include <stdint.h>
  13 #include <stdbool.h>
  14 #include <common/macros.h>
  15 #include <common/trace-chunk.h>
  16
  17 #ifdef __cplusplus
  18 extern "C" {
  19 #endif
  20
  21 struct lttng_trace_chunk_registry;
  22
  23 /*
  24  * Create an lttng_trace_chunk registry.
  25  *
  26  * A trace chunk registry maintains an association between a
  27  * (session_id, chunk_id) tuple and a trace chunk object. The chunk_id can
  28  * be "unset" in the case of an anonymous trace chunk.
  29  *
  30  * Note that a trace chunk registry holds no ownership of its trace
  31  * chunks. Trace chunks are unpublished when their last reference is released.
  32  * See the documentation of lttng_trace_chunk.
  33  *
  34  * Returns a trace chunk registry on success, NULL on error.
  35  *
  36  * Note that a trace chunk registry may only be accessed by an RCU thread.
  37  */
  38 struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void);
  39
  40 /*
  41  * Destroy an lttng trace chunk registry. The registry must be emptied
  42  * (i.e. all references to the trace chunks it contains must be released) before
  43  * it is destroyed.
  44  */
  45 void lttng_trace_chunk_registry_destroy(
  46                 struct lttng_trace_chunk_registry *registry);
  47
  48 /*
  49  * Publish a trace chunk for a given session id.
  50  * A reference is acquired on behalf of the caller.
  51  *
  52  * The trace chunk that is returned is the published version of the trace
  53  * chunk. The chunk provided should be discarded on success and it's
  54  * published version used in its place.
  55  *
  56  * See the documentation of lttng_trace_chunk for more information on
  57  * the usage of the various parameters.
  58  *
  59  * Returns an lttng_trace_chunk on success, NULL on error.
  60  */
  61 struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk(
  62                 struct lttng_trace_chunk_registry *registry,
  63                 uint64_t session_id, struct lttng_trace_chunk *chunk);
  64
  65 /*
  66  * Look-up a trace chunk by session_id and chunk_id.
  67  * A reference is acquired on behalf of the caller.
  68  *
  69  * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
  70  */
  71 struct lttng_trace_chunk *
  72 lttng_trace_chunk_registry_find_chunk(
  73                 const struct lttng_trace_chunk_registry *registry,
  74                 uint64_t session_id, uint64_t chunk_id);
  75
  76 /*
  77  * Query the existence of a trace chunk by session_id and chunk_id.
  78  *
  79  * Returns 0 on success, a negative value on error.
  80  */
  81 int lttng_trace_chunk_registry_chunk_exists(
  82                 const struct lttng_trace_chunk_registry *registry,
  83                 uint64_t session_id, uint64_t chunk_id, bool *chunk_exists);
  84
  85 /*
  86  * Look-up an anonymous trace chunk by session_id.
  87  * A reference is acquired on behalf of the caller.
  88  *
  89  * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
  90  */
  91 struct lttng_trace_chunk *
  92 lttng_trace_chunk_registry_find_anonymous_chunk(
  93                 const struct lttng_trace_chunk_registry *registry,
  94                 uint64_t session_id);
  95
  96 unsigned int lttng_trace_chunk_registry_put_each_chunk(
  97                 const struct lttng_trace_chunk_registry *registry);
  98
  99 #ifdef __cplusplus
 100 }
 101 #endif
 102
 103 #endif /* LTTNG_TRACE_CHUNK_REGISTRY_H */