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 struct lttng_trace_chunk_registry;
  18
  19 /*
  20  * Create an lttng_trace_chunk registry.
  21  *
  22  * A trace chunk registry maintains an association between a
  23  * (session_id, chunk_id) tuple and a trace chunk object. The chunk_id can
  24  * be "unset" in the case of an anonymous trace chunk.
  25  *
  26  * Note that a trace chunk registry holds no ownership of its trace
  27  * chunks. Trace chunks are unpublished when their last reference is released.
  28  * See the documentation of lttng_trace_chunk.
  29  *
  30  * Returns a trace chunk registry on success, NULL on error.
  31  *
  32  * Note that a trace chunk registry may only be accessed by an RCU thread.
  33  */
  34 LTTNG_HIDDEN
  35 struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void);
  36
  37 /*
  38  * Destroy an lttng trace chunk registry. The registry must be emptied
  39  * (i.e. all references to the trace chunks it contains must be released) before
  40  * it is destroyed.
  41  */
  42 LTTNG_HIDDEN
  43 void lttng_trace_chunk_registry_destroy(
  44                 struct lttng_trace_chunk_registry *registry);
  45
  46 /*
  47  * Publish a trace chunk for a given session id.
  48  * A reference is acquired on behalf of the caller.
  49  *
  50  * The trace chunk that is returned is the published version of the trace
  51  * chunk. The chunk provided should be discarded on success and it's
  52  * published version used in its place.
  53  *
  54  * See the documentation of lttng_trace_chunk for more information on
  55  * the usage of the various parameters.
  56  *
  57  * Returns an lttng_trace_chunk on success, NULL on error.
  58  */
  59 LTTNG_HIDDEN
  60 struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk(
  61                 struct lttng_trace_chunk_registry *registry,
  62                 uint64_t session_id, struct lttng_trace_chunk *chunk);
  63
  64 /*
  65  * Look-up a trace chunk by session_id and chunk_id.
  66  * A reference is acquired on behalf of the caller.
  67  *
  68  * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
  69  */
  70 LTTNG_HIDDEN
  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 LTTNG_HIDDEN
  82 int lttng_trace_chunk_registry_chunk_exists(
  83                 const struct lttng_trace_chunk_registry *registry,
  84                 uint64_t session_id, uint64_t chunk_id, bool *chunk_exists);
  85
  86 /*
  87  * Look-up an anonymous trace chunk by session_id.
  88  * A reference is acquired on behalf of the caller.
  89  *
  90  * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
  91  */
  92 LTTNG_HIDDEN
  93 struct lttng_trace_chunk *
  94 lttng_trace_chunk_registry_find_anonymous_chunk(
  95                 const struct lttng_trace_chunk_registry *registry,
  96                 uint64_t session_id);
  97
  98 LTTNG_HIDDEN
  99 unsigned int lttng_trace_chunk_registry_put_each_chunk(
 100                 const struct lttng_trace_chunk_registry *registry);
 101
 102 #endif /* LTTNG_TRACE_CHUNK_REGISTRY_H */