include/lttng/clear.h

   1 /*
   2  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  * Copyright (C) 2019 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * SPDX-License-Identifier: LGPL-2.1-only
   6  *
   7  */
   8
   9 #ifndef LTTNG_CLEAR_H
  10 #define LTTNG_CLEAR_H
  11
  12 #include <lttng/lttng-error.h>
  13
  14 #ifdef __cplusplus
  15 extern "C" {
  16 #endif
  17
  18 struct lttng_clear_handle;
  19
  20 /*
  21  * Clear a tracing session.
  22  *
  23  * Clear the data buffers and trace data.
  24  *
  25  * For sessions saving trace data to disk and streaming over the network to a
  26  * relay daemon, the buffers content and existing stream files are cleared when
  27  * the clear command is issued.
  28  *
  29  * For snapshot sessions (flight recorder), only the buffer content is cleared.
  30  * Prior snapshots are individually recorded to disk, and are therefore
  31  * untouched by this "clear" command.
  32  *
  33  * For live sessions streaming over network to a relay daemon, the buffers
  34  * will be cleared and the files on the relay daemon side will be cleared as
  35  * well. However, any active live trace viewer currently reading an existing
  36  * trace packet will be able to proceed to read that packet entirely before
  37  * skipping over cleared stream data.
  38  *
  39  * The clear command guarantees that no trace data produced before this function
  40  * is called will be present in the resulting trace.
  41  *
  42  * Trace data produced between the moment this function is called and when it
  43  * returns might be present in the resulting trace.
  44  *
  45  * Provides an lttng_clear_handle which can be used to wait for the completion
  46  * of the session's clear.
  47  *
  48  * Return LTTNG_OK on success else a negative LTTng error code. The returned
  49  * handle is owned by the caller and must be free'd using
  50  * lttng_clear_handle_destroy().
  51  *
  52  * Important error codes:
  53  *    LTTNG_ERR_CLEAR_RELAY_DISALLOWED
  54  *    LTTNG_ERR_CLEAR_NOT_AVAILABLE_RELAY
  55  *    LTTNG_ERR_CLEAR_FAIL_CONSUMER
  56 */
  57 extern enum lttng_error_code lttng_clear_session(const char *session_name,
  58                 struct lttng_clear_handle **handle);
  59
  60 #endif /* LTTNG_CLEAR_H */