include/lttng/session-descriptor.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_SESSION_DESCRIPTOR_H
   9 #define LTTNG_SESSION_DESCRIPTOR_H
  10
  11 #ifdef __cplusplus
  12 extern "C" {
  13 #endif
  14
  15 struct lttng_session_descriptor;
  16
  17 /*
  18  * Session descriptor API.
  19  *
  20  * A session descriptor is an object describing the immutable configuration
  21  * options of an LTTng tracing session.
  22  *
  23  * When used with the lttng_create_session_ext() function, a session descriptor
  24  * allows the creation of a tracing session of the following types: regular,
  25  * snapshot, and live.
  26  *
  27  * Certain parameters can be omitted at the time of creation of a session
  28  * descriptor to use default or auto-generated values selected by the
  29  * session daemon. For instance, a session's name can be left unspecified,
  30  * in which case one that is guaranteed not to clash with pre-existing
  31  * sessions will be automatically be generated by the session daemon.
  32  *
  33  * Most session descriptors can be created in either "no output", local, or
  34  * network output modes. The various output modes supported vary by session
  35  * type.
  36  *
  37  * Regular session creation functions and output modes:
  38  *   * "no output": lttng_session_descriptor_create()
  39  *   * local:       lttng_session_descriptor_local_create()
  40  *   * network:     lttng_session_descriptor_network_create()
  41  *
  42  * Snapshot session creation functions and output modes:
  43  *   * "no output": lttng_session_descriptor_snapshot_create()
  44  *   * local:       lttng_session_descriptor_snapshot_local_create()
  45  *   * network:     lttng_session_descriptor_snapshot_network_create()
  46  *
  47  * Live session creation functions and output modes:
  48  *   * "no output": lttng_session_descriptor_live_create()
  49  *   * network:     lttng_session_descriptor_live_network_create()
  50  *
  51  * Local output functions accept a 'path' parameter that must be an absolute
  52  * path to which the user has write access. When a local output is automatically
  53  * generated, it adopts the form:
  54  *   $LTTNG_HOME/DEFAULT_TRACE_DIR_NAME/SESSION_NAME-CREATION_TIME
  55  *
  56  * Where CREATION_TIME is time of the creation of the session on the session
  57  * daemon in the form "yyyymmdd-hhmmss".
  58  *
  59  * Network output locations can also be auto-generated by leaving the
  60  * 'control_url' and 'data_url' output parameters unspecified. In such cases,
  61  * the session daemon will create a default output targeting a relay daemon
  62  * at net://127.0.0.1, using the default 'control' and 'data' ports.
  63  *
  64  * The format of the 'control_url' and 'data_url' parameters is:
  65  *   NETPROTO://(HOST | IPADDR)[:CTRLPORT[:DATAPORT]][/TRACEPATH]
  66  *
  67  * NETPROTO: Network protocol, amongst:
  68  *   * net:  TCP over IPv4; the default values of 'CTRLPORT' and 'DATAPORT'
  69  *           are defined at build time of the lttng toolchain.
  70  *   * net6: TCP over IPv6: same default ports as the 'net' protocol.
  71  *   * tcp:  Same as the 'net' protocol.
  72  *   * tcp6: Same as the 'net6' protocol.
  73  *
  74  * HOST | IPADDR:  Hostname or IP address (IPv6 address *must* be enclosed
  75  *                 in brackets; see RFC 2732).
  76  *
  77  * CTRLPORT: Control port.
  78  *
  79  * DATAPORT: Data port.
  80  *
  81  * TRACEPATH: Path of trace files on the remote file system. This path is
  82  *            relative to the base output directory set on the relay daemon
  83  *            end.
  84  *
  85  * The 'data_url' parameter is optional:
  86  *   * This parameter is meaningless for local tracing.
  87  *   * If 'control_url' is specified and a network protocol is used, the
  88  *     default data port, and the 'control_url' host will be used.
  89  */
  90
  91 enum lttng_session_descriptor_status {
  92         /* Invalid session descriptor parameter. */
  93         LTTNG_SESSION_DESCRIPTOR_STATUS_INVALID = -1,
  94         LTTNG_SESSION_DESCRIPTOR_STATUS_OK = 0,
  95         /* Session descriptor parameter is unset. */
  96         LTTNG_SESSION_DESCRIPTOR_STATUS_UNSET = 1,
  97 };
  98
  99 /*
 100  * Create a session descriptor in no-output mode.
 101  *
 102  * The 'name' parameter can be left NULL to auto-generate a session name.
 103  *
 104  * Returns an lttng_session_descriptor instance on success, NULL on error.
 105  */
 106 extern struct lttng_session_descriptor *
 107 lttng_session_descriptor_create(const char *name);
 108
 109 /*
 110  * Create a session descriptor with a local output destination.
 111  *
 112  * The 'name' parameter can be left NULL to auto-generate a session name.
 113  *
 114  * The 'path' must either be an absolute path or it can be left NULL to
 115  * use the default local output destination.
 116  *
 117  * Returns an lttng_session_descriptor instance on success, NULL on error.
 118  */
 119 extern struct lttng_session_descriptor *
 120 lttng_session_descriptor_local_create(const char *name, const char *path);
 121
 122 /*
 123  * Create a session descriptor with a remote output destination.
 124  *
 125  * The 'name' parameter can be left NULL to auto-generate a session name.
 126  *
 127  * The 'control_url' and 'data_url' must conform to the URL format
 128  * described above or can be left NULL to use the default network output.
 129  *
 130  * Returns an lttng_session_descriptor instance on success, NULL on error.
 131  */
 132 extern struct lttng_session_descriptor *
 133 lttng_session_descriptor_network_create(const char *name,
 134                 const char *control_url, const char *data_url);
 135
 136 /*
 137  * Create a snapshot session descriptor without a default output.
 138  *
 139  * The 'name' parameter can be left NULL to auto-generate a session name.
 140  *
 141  * Returns an lttng_session_descriptor instance on success, NULL on error.
 142  */
 143 extern struct lttng_session_descriptor *
 144 lttng_session_descriptor_snapshot_create(const char *name);
 145
 146 /*
 147  * Create a snapshot session descriptor with a local output destination.
 148  *
 149  * The 'name' parameter can be left NULL to auto-generate a session name.
 150  *
 151  * The 'path' must either be an absolute path or it can be left NULL to
 152  * use the default local output destination as the default snapshot output.
 153  *
 154  * Returns an lttng_session_descriptor instance on success, NULL on error.
 155  */
 156 extern struct lttng_session_descriptor *
 157 lttng_session_descriptor_snapshot_local_create(const char *name,
 158                 const char *path);
 159
 160 /*
 161  * Create a snapshot session descriptor with a remote output destination.
 162  *
 163  * The 'name' parameter can be left NULL to auto-generate a session name.
 164  *
 165  * The 'control_url' and 'data_url' must conform to the URL format
 166  * described above or can be left NULL to use the default network output as
 167  * the default snapshot output.
 168  *
 169  * Returns an lttng_session_descriptor instance on success, NULL on error.
 170  */
 171 extern struct lttng_session_descriptor *
 172 lttng_session_descriptor_snapshot_network_create(const char *name,
 173                 const char *control_url, const char *data_url);
 174
 175 /*
 176  * Create a live session descriptor without an output.
 177  *
 178  * The 'name' parameter can be left NULL to auto-generate a session name.
 179  *
 180  * The 'live_timer_interval_us' parameter is the live timer's period, specified
 181  * in microseconds.
 182  *
 183  * This parameter can't be 0. There is no default value defined for a live
 184  * timer's period.
 185  *
 186  * Returns an lttng_session_descriptor instance on success, NULL on error.
 187  */
 188 extern struct lttng_session_descriptor *
 189 lttng_session_descriptor_live_create(
 190                 const char *name, unsigned long long live_timer_interval_us);
 191
 192 /*
 193  * Create a live session descriptor with a remote output destination.
 194  *
 195  * The 'name' parameter can be left NULL to auto-generate a session name.
 196  *
 197  * The 'control_url' and 'data_url' must conform to the URL format
 198  * described above or can be left NULL to use the default network output.
 199  *
 200  * The 'live_timer_interval_us' parameter is the live timer's period, specified
 201  * in microseconds.
 202  *
 203  * This parameter can't be 0. There is no default value defined for a live
 204  * timer's period.
 205  *
 206  * Returns an lttng_session_descriptor instance on success, NULL on error.
 207  */
 208 extern struct lttng_session_descriptor *
 209 lttng_session_descriptor_live_network_create(
 210                 const char *name,
 211                 const char *control_url, const char *data_url,
 212                 unsigned long long live_timer_interval_us);
 213
 214 /*
 215  * Get a session descriptor's session name.
 216  *
 217  * The 'name' parameter is used as an output parameter and will point to
 218  * the session descriptor's session name on success
 219  * (LTTNG_SESSION_DESCRIPTOR_STATUS_OK). Its content of is left unspecified
 220  * for other return codes. The pointer returned through 'name' is only
 221  * guaranteed to remain valid until the next method call on the session
 222  * descriptor.
 223  *
 224  * Returns LTTNG_SESSION_DESCRIPTOR_STATUS_OK on success,
 225  * LTTNG_SESSION_DESCRIPTOR_STATUS_INVALID if 'descriptor' or 'name' are
 226  * NULL, and LTTNG_SESSION_DESCRIPTOR_STATUS_UNSET if the descriptor's
 227  * name parameter is unset.
 228  */
 229 extern enum lttng_session_descriptor_status
 230 lttng_session_descriptor_get_session_name(
 231                 const struct lttng_session_descriptor *descriptor,
 232                 const char **name);
 233
 234 /*
 235  * Destroy a local lttng_session object.
 236  *
 237  * This does not destroy the session on the session daemon; it releases
 238  * the resources allocated by the descriptor object.
 239  */
 240 extern void lttng_session_descriptor_destroy(
 241                 struct lttng_session_descriptor *descriptor);
 242
 243 #ifdef __cplusplus
 244 }
 245 #endif
 246
 247 #endif /* LTTNG_SESSION_DESCRIPTOR_H */