include/lttng/lttng.h

   1 /*
   2  * lttng.h
   3  *
   4  * Linux Trace Toolkit Control Library Header File
   5  *
   6  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   7  *
   8  * This library is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License, version 2.1 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This library is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  15  * for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this library; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef LTTNG_H
  23 #define LTTNG_H
  24
  25 /* Error codes that can be returned by API calls */
  26 #include <lttng/lttng-error.h>
  27
  28 /* Include every LTTng ABI/API available. */
  29 #include <lttng/channel.h>
  30 #include <lttng/domain.h>
  31 #include <lttng/event.h>
  32 #include <lttng/handle.h>
  33 #include <lttng/health.h>
  34 #include <lttng/save.h>
  35 #include <lttng/session.h>
  36 #include <lttng/snapshot.h>
  37
  38 #ifdef __cplusplus
  39 extern "C" {
  40 #endif
  41
  42 enum lttng_calibrate_type {
  43         LTTNG_CALIBRATE_FUNCTION              = 0,
  44 };
  45
  46 #define LTTNG_CALIBRATE_PADDING1           16
  47 struct lttng_calibrate {
  48         enum lttng_calibrate_type type;
  49
  50         char padding[LTTNG_CALIBRATE_PADDING1];
  51 };
  52
  53 /*
  54  * Check if a session daemon is alive.
  55  *
  56  * Return 1 if alive or 0 if not. On error, returns a negative negative LTTng
  57  * error code.
  58  */
  59 extern int lttng_session_daemon_alive(void);
  60
  61 /*
  62  * Set the tracing group for the *current* flow of execution.
  63  *
  64  * On success, returns 0 else a negative LTTng error code.
  65  */
  66 extern int lttng_set_tracing_group(const char *name);
  67
  68 /*
  69  * This call registers an "outside consumer" for a session and an lttng domain.
  70  * No consumer will be spawned and all fds/commands will go through the socket
  71  * path given (socket_path).
  72  *
  73  * NOTE that this is not recommended unless you absolutely know what you are
  74  * doing.
  75  *
  76  * Return 0 on success else a negative LTTng error code.
  77  */
  78 extern int lttng_register_consumer(struct lttng_handle *handle,
  79                 const char *socket_path);
  80
  81 /*
  82  * Start tracing for *all* domain(s) in the session.
  83  *
  84  * Return 0 on success else a negative LTTng error code.
  85  */
  86 extern int lttng_start_tracing(const char *session_name);
  87
  88 /*
  89  * Stop tracing for *all* domain(s) in the session.
  90  *
  91  * This call will wait for data availability for each domain of the session so
  92  * this can take an abritrary amount of time. However, when returning you have
  93  * the guarantee that the data is ready to be read and analyze. Use the
  94  * _no_wait call below to avoid this behavior.
  95  *
  96  * The session_name can't be NULL.
  97  *
  98  * Return 0 on success else a negative LTTng error code.
  99  */
 100 extern int lttng_stop_tracing(const char *session_name);
 101
 102 /*
 103  * Behave exactly like lttng_stop_tracing but does not wait for data
 104  * availability.
 105  */
 106 extern int lttng_stop_tracing_no_wait(const char *session_name);
 107
 108 /*
 109  * Calibrate LTTng overhead.
 110  *
 111  * The chan and handle params can not be NULL.
 112  *
 113  * Return 0 on success else a negative LTTng error code.
 114  */
 115 extern int lttng_calibrate(struct lttng_handle *handle,
 116                 struct lttng_calibrate *calibrate);
 117
 118 /*
 119  * Set URL for a consumer for a session and domain.
 120  *
 121  * Both data and control URL must be defined. If both URLs are the same, only
 122  * the control URL is used even for network streaming.
 123  *
 124  * Default port are 5342 and 5343 respectively for control and data which uses
 125  * the TCP protocol.
 126  *
 127  * URL format: proto://[HOST|IP][:PORT1[:PORT2]][/TRACE_PATH]
 128  *
 129  * Possible protocols are:
 130  * > file://...
 131  *   Local filesystem full path.
 132  *
 133  * > net[6]://...
 134  *   This will use the default network transport layer which is TCP for both
 135  *   control (PORT1) and data port (PORT2).
 136  *
 137  * > tcp[6]://...
 138  *   TCP only streaming. For this one, both data and control URL must be given.
 139  *
 140  * Return 0 on success else a negative LTTng error code.
 141  */
 142 extern int lttng_set_consumer_url(struct lttng_handle *handle,
 143                 const char *control_url, const char *data_url);
 144
 145 /*
 146  * For a given session name, this call checks if the data is ready to be read
 147  * or is still being extracted by the consumer(s) (pending) hence not ready to
 148  * be used by any readers.
 149  *
 150  * Return 0 if there is _no_ data pending in the buffers thus having a
 151  * guarantee that the data can be read safely. Else, return 1 if there is still
 152  * traced data is pending. On error, a negative value is returned and readable
 153  * by lttng_strerror().
 154  */
 155 extern int lttng_data_pending(const char *session_name);
 156
 157 #ifdef __cplusplus
 158 }
 159 #endif
 160
 161 #endif /* LTTNG_H */