src/common/mi-lttng.h

   1 /*
   2  * Copyright (C) 2014 - Jonathan Rajotte <jonathan.r.julien@gmail.com>
   3  *                    - Olivier Cotte <olivier.cotte@polymtl.ca>
   4  * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef _MI_LTTNG_H
  21 #define _MI_LTTNG_H
  22
  23 #include <stdint.h>
  24
  25 #include <common/error.h>
  26 #include <common/macros.h>
  27 #include <common/config/session-config.h>
  28 #include <lttng/lttng.h>
  29
  30 /* Don't want to reference snapshot-internal.h here */
  31 struct lttng_snapshot_output;
  32
  33 /* Instance of a machine interface writer. */
  34 struct mi_writer {
  35         struct config_writer *writer;
  36         enum lttng_mi_output_type type;
  37 };
  38
  39 /*
  40  * Version information for the machine interface.
  41  */
  42 struct mi_lttng_version {
  43         char version[LTTNG_NAME_MAX]; /* Version number of package */
  44         uint32_t version_major; /* LTTng-Tools major version number */
  45         uint32_t version_minor; /* LTTng-Tools minor version number */
  46         uint32_t version_patchlevel; /* LTTng-Tools patchlevel version number */
  47         char version_commit[LTTNG_NAME_MAX]; /* Commit hash of the current version */
  48         char version_name[LTTNG_NAME_MAX];
  49         char package_url[LTTNG_NAME_MAX]; /* Define to the home page for this package. */
  50 };
  51
  52 /* Strings related to command */
  53 extern const char * const mi_lttng_element_command;
  54 extern const char * const mi_lttng_element_command_action;
  55 extern const char * const mi_lttng_element_command_add_context;
  56 extern const char * const mi_lttng_element_command_create;
  57 extern const char * const mi_lttng_element_command_destroy;
  58 extern const char * const mi_lttng_element_command_disable_channel;
  59 extern const char * const mi_lttng_element_command_disable_event;
  60 extern const char * const mi_lttng_element_command_enable_channels;
  61 extern const char * const mi_lttng_element_command_enable_event;
  62 extern const char * const mi_lttng_element_command_list;
  63 extern const char * const mi_lttng_element_command_load;
  64 extern const char * const mi_lttng_element_command_metadata;
  65 extern const char * const mi_lttng_element_command_metadata_action;
  66 extern const char * const mi_lttng_element_command_regenerate;
  67 extern const char * const mi_lttng_element_command_regenerate_action;
  68 extern const char * const mi_lttng_element_command_name;
  69 extern const char * const mi_lttng_element_command_output;
  70 extern const char * const mi_lttng_element_command_save;
  71 extern const char * const mi_lttng_element_command_set_session;
  72 extern const char * const mi_lttng_element_command_snapshot;
  73 extern const char * const mi_lttng_element_command_snapshot_add;
  74 extern const char * const mi_lttng_element_command_snapshot_del;
  75 extern const char * const mi_lttng_element_command_snapshot_list;
  76 extern const char * const mi_lttng_element_command_snapshot_record;
  77 extern const char * const mi_lttng_element_command_start;
  78 extern const char * const mi_lttng_element_command_stop;
  79 extern const char * const mi_lttng_element_command_success;
  80 extern const char * const mi_lttng_element_command_track;
  81 extern const char * const mi_lttng_element_command_untrack;
  82 extern const char * const mi_lttng_element_command_version;
  83 extern const char * const mi_lttng_element_command_rotate;
  84
  85 /* Strings related to version command */
  86 extern const char * const mi_lttng_element_version;
  87 extern const char * const mi_lttng_element_version_commit;
  88 extern const char * const mi_lttng_element_version_description;
  89 extern const char * const mi_lttng_element_version_license;
  90 extern const char * const mi_lttng_element_version_major;
  91 extern const char * const mi_lttng_element_version_minor;
  92 extern const char * const mi_lttng_element_version_patch_level;
  93 extern const char * const mi_lttng_element_version_str;
  94 extern const char * const mi_lttng_element_version_web;
  95
  96 /* String related to a lttng_event_field */
  97 extern const char * const mi_lttng_element_event_field;
  98 extern const char * const mi_lttng_element_event_fields;
  99
 100 /* String related to lttng_event_perf_counter_ctx */
 101 extern const char * const mi_lttng_element_perf_counter_context;
 102
 103 /* Strings related to pid */
 104 extern const char * const mi_lttng_element_pid_id;
 105
 106 /* Strings related to save command */
 107 extern const char * const mi_lttng_element_save;
 108
 109 /* Strings related to load command */
 110 extern const char * const mi_lttng_element_load;
 111 LTTNG_HIDDEN const char * const mi_lttng_element_load_overrides;
 112 LTTNG_HIDDEN const char * const mi_lttng_element_load_override_url;
 113
 114 /* General element of mi_lttng */
 115 extern const char * const mi_lttng_element_empty;
 116 extern const char * const mi_lttng_element_id;
 117 extern const char * const mi_lttng_element_nowrite;
 118 extern const char * const mi_lttng_element_success;
 119 extern const char * const mi_lttng_element_type_enum;
 120 extern const char * const mi_lttng_element_type_float;
 121 extern const char * const mi_lttng_element_type_integer;
 122 extern const char * const mi_lttng_element_type_other;
 123 extern const char * const mi_lttng_element_type_string;
 124
 125 /* String related to loglevel */
 126 extern const char * const mi_lttng_loglevel_str_alert;
 127 extern const char * const mi_lttng_loglevel_str_crit;
 128 extern const char * const mi_lttng_loglevel_str_debug;
 129 extern const char * const mi_lttng_loglevel_str_debug_function;
 130 extern const char * const mi_lttng_loglevel_str_debug_line;
 131 extern const char * const mi_lttng_loglevel_str_debug_module;
 132 extern const char * const mi_lttng_loglevel_str_debug_process;
 133 extern const char * const mi_lttng_loglevel_str_debug_program;
 134 extern const char * const mi_lttng_loglevel_str_debug_system;
 135 extern const char * const mi_lttng_loglevel_str_debug_unit;
 136 extern const char * const mi_lttng_loglevel_str_emerg;
 137 extern const char * const mi_lttng_loglevel_str_err;
 138 extern const char * const mi_lttng_loglevel_str_info;
 139 extern const char * const mi_lttng_loglevel_str_notice;
 140 extern const char * const mi_lttng_loglevel_str_unknown;
 141 extern const char * const mi_lttng_loglevel_str_warning;
 142
 143 /* String related to loglevel JUL */
 144 extern const char * const mi_lttng_loglevel_str_jul_all;
 145 extern const char * const mi_lttng_loglevel_str_jul_config;
 146 extern const char * const mi_lttng_loglevel_str_jul_fine;
 147 extern const char * const mi_lttng_loglevel_str_jul_finer;
 148 extern const char * const mi_lttng_loglevel_str_jul_finest;
 149 extern const char * const mi_lttng_loglevel_str_jul_info;
 150 extern const char * const mi_lttng_loglevel_str_jul_off;
 151 extern const char * const mi_lttng_loglevel_str_jul_severe;
 152 extern const char * const mi_lttng_loglevel_str_jul_warning;
 153
 154 /* String related to loglevel Log4j */
 155 extern const char * const mi_lttng_loglevel_str_log4j_off;
 156 extern const char * const mi_lttng_loglevel_str_log4j_fatal;
 157 extern const char * const mi_lttng_loglevel_str_log4j_error;
 158 extern const char * const mi_lttng_loglevel_str_log4j_warn;
 159 extern const char * const mi_lttng_loglevel_str_log4j_info;
 160 extern const char * const mi_lttng_loglevel_str_log4j_debug;
 161 extern const char * const mi_lttng_loglevel_str_log4j_trace;
 162 extern const char * const mi_lttng_loglevel_str_log4j_all;
 163
 164 /* String related to loglevel Python */
 165 extern const char * const mi_lttng_loglevel_str_python_critical;
 166 extern const char * const mi_lttng_loglevel_str_python_error;
 167 extern const char * const mi_lttng_loglevel_str_python_warning;
 168 extern const char * const mi_lttng_loglevel_str_python_info;
 169 extern const char * const mi_lttng_loglevel_str_python_debug;
 170 extern const char * const mi_lttng_loglevel_str_python_notset;
 171
 172 /* String related to loglevel type */
 173 extern const char * const mi_lttng_loglevel_type_all;
 174 extern const char * const mi_lttng_loglevel_type_range;
 175 extern const char * const mi_lttng_loglevel_type_single;
 176 extern const char * const mi_lttng_loglevel_type_unknown;
 177
 178 /* String related to a lttng_snapshot */
 179 extern const char * const mi_lttng_element_snapshot_ctrl_url;
 180 extern const char * const mi_lttng_element_snapshot_data_url;
 181 extern const char * const mi_lttng_element_snapshot_max_size;
 182 extern const char * const mi_lttng_element_snapshot_n_ptr;
 183 extern const char * const mi_lttng_element_snapshot_session_name;
 184 extern const char * const mi_lttng_element_snapshots;
 185
 186 /* String related to track/untrack command */
 187 const char * const mi_lttng_element_track_untrack_all_wildcard;
 188
 189 LTTNG_HIDDEN const char * const mi_lttng_element_session_name;
 190
 191 /* String related to rotate command */
 192 LTTNG_HIDDEN const char * const mi_lttng_element_rotation;
 193 LTTNG_HIDDEN const char * const mi_lttng_element_rotations;
 194 LTTNG_HIDDEN const char * const mi_lttng_element_rotate_status;
 195
 196 /* Utility string function  */
 197 const char *mi_lttng_loglevel_string(int value, enum lttng_domain_type domain);
 198 const char *mi_lttng_logleveltype_string(enum lttng_loglevel_type value);
 199 const char *mi_lttng_eventfieldtype_string(enum lttng_event_field_type value);
 200 const char *mi_lttng_domaintype_string(enum lttng_domain_type value);
 201 const char *mi_lttng_buffertype_string(enum lttng_buffer_type value);
 202
 203 /*
 204  * Create an instance of a machine interface writer.
 205  *
 206  * fd_output File to which the XML content must be written. The file will be
 207  * closed once the mi_writer has been destroyed.
 208  *
 209  * Returns an instance of a machine interface writer on success, NULL on
 210  * error.
 211  */
 212 struct mi_writer *mi_lttng_writer_create(int fd_output, int mi_output_type);
 213
 214 /*
 215  * Destroy an instance of a machine interface writer.
 216  *
 217  * writer An instance of a machine interface writer.
 218  *
 219  * Returns zero if the XML document could be closed cleanly. Negative values
 220  * indicate an error.
 221  */
 222 int mi_lttng_writer_destroy(struct mi_writer *writer);
 223
 224 /*
 225  * Open a command tag and add it's name node.
 226  *
 227  * writer An instance of a machine interface writer.
 228  * command The command name.
 229  *
 230  * Returns zero if the XML document could be closed cleanly.
 231  * Negative values indicate an error.
 232  */
 233 int mi_lttng_writer_command_open(struct mi_writer *writer, const char *command);
 234
 235 /*
 236  * Close a command tag.
 237  *
 238  * writer An instance of a machine interface writer.
 239  *
 240  * Returns zero if the XML document could be closed cleanly.
 241  * Negative values indicate an error.
 242  */
 243 int mi_lttng_writer_command_close(struct mi_writer *writer);
 244
 245 /*
 246  * Open an element tag.
 247  *
 248  * writer An instance of a machine interface writer.
 249  * element_name Element tag name.
 250  *
 251  * Returns zero if the XML document could be closed cleanly.
 252  * Negative values indicate an error.
 253  */
 254 int mi_lttng_writer_open_element(struct mi_writer *writer,
 255                 const char *element_name);
 256
 257 /*
 258  * Close the current element tag.
 259  *
 260  * writer An instance of a machine interface writer.
 261  *
 262  * Returns zero if the XML document could be closed cleanly.
 263  * Negative values indicate an error.
 264  */
 265 int mi_lttng_writer_close_element(struct mi_writer *writer);
 266
 267 /*
 268  * Close multiple element.
 269  *
 270  * writer An instance of a machine interface writer.
 271  * nb_element Number of elements.
 272  *
 273  * Returns zero if the XML document could be closed cleanly.
 274  * Negative values indicate an error.
 275  */
 276 int mi_lttng_close_multi_element(struct mi_writer *writer,
 277                 unsigned int nb_element);
 278
 279 /*
 280  * Write an element of type unsigned int.
 281  *
 282  * writer An instance of a machine interface writer.
 283  * element_name Element name.
 284  * value Unsigned int value of the element
 285  *
 286  * Returns zero if the element's value could be written.
 287  * Negative values indicate an error.
 288  */
 289 int mi_lttng_writer_write_element_unsigned_int(struct mi_writer *writer,
 290                 const char *element_name, uint64_t value);
 291
 292 /*
 293  * Write an element of type signed int.
 294  *
 295  * writer An instance of a machine interface writer.
 296  * element_name Element name.
 297  * value Signed int value of the element.
 298  *
 299  * Returns zero if the element's value could be written.
 300  * Negative values indicate an error.
 301  */
 302 int mi_lttng_writer_write_element_signed_int(struct mi_writer *writer,
 303                 const char *element_name, int64_t value);
 304
 305 /*
 306  * Write an element of type boolean.
 307  *
 308  * writer An instance of a machine interface writer.
 309  * element_name Element name.
 310  * value Boolean value of the element.
 311  *
 312  * Returns zero if the element's value could be written.
 313  * Negative values indicate an error.
 314  */
 315 int mi_lttng_writer_write_element_bool(struct mi_writer *writer,
 316                 const char *element_name, int value);
 317
 318 /*
 319  * Write an element of type string.
 320  *
 321  * writer An instance of a machine interface writer.
 322  * element_name Element name.
 323  * value String value of the element.
 324  *
 325  * Returns zero if the element's value could be written.
 326  * Negative values indicate an error.
 327  */
 328 int mi_lttng_writer_write_element_string(struct mi_writer *writer,
 329                 const char *element_name, const char *value);
 330
 331 /*
 332  * Machine interface of struct version.
 333  *
 334  * writer An instance of a machine interface writer.
 335  * version Version struct.
 336  * lttng_description String value of the version description.
 337  * lttng_license String value of the version license.
 338  *
 339  * Returns zero if the element's value could be written.
 340  * Negative values indicate an error.
 341  */
 342 int mi_lttng_version(struct mi_writer *writer, struct mi_lttng_version *version,
 343                 const char *lttng_description, const char *lttng_license);
 344
 345 /*
 346  * Machine interface: open a sessions element.
 347  *
 348  * writer An instance of a machine interface writer.
 349  *
 350  * Returns zero if the element's value could be written.
 351  * Negative values indicate an error.
 352  */
 353 int mi_lttng_sessions_open(struct mi_writer *writer);
 354
 355 /*
 356  * Machine interface of struct session.
 357  *
 358  * writer An instance of a machine interface writer.
 359  * session An instance of a session.
 360  * is_open Defines whether or not the session element shall be closed.
 361  *         This should be used carefully and the client
 362  *         must close the session element.
 363  *         Use case: nested additional information on a session
 364  *                  ex: domain,channel event.
 365  *
 366  * Returns zero if the element's value could be written.
 367  * Negative values indicate an error.
 368  */
 369 int mi_lttng_session(struct mi_writer *writer,
 370                 struct lttng_session *session, int is_open);
 371
 372 /*
 373  * Machine interface: open a domains element.
 374  *
 375  * writer An instance of a machine interface writer.
 376  *
 377  * Returns zero if the element's value could be written.
 378  * Negative values indicate an error.
 379  */
 380 int mi_lttng_domains_open(struct mi_writer *writer);
 381
 382 /*
 383  * Machine interface of struct domain.
 384  *
 385  * writer An instance of a machine interface writer.
 386  * domain An instance of a domain.
 387  *
 388  * is_open Defines whether or not the session element shall be closed.
 389  *         This should be used carefully and the client
 390  *         must close the domain element.
 391  *         Use case: nested addition information on a domain
 392  *                  ex: channel event.
 393  *
 394  * Returns zero if the element's value could be written.
 395  * Negative values indicate an error.
 396  */
 397 int mi_lttng_domain(struct mi_writer *writer,
 398                 struct lttng_domain *domain, int is_open);
 399
 400 /*
 401  * Machine interface: open a channels element.
 402  *
 403  * writer An instance of a machine interface writer.
 404  *
 405  * Returns zero if the element's value could be written.
 406  * Negative values indicate an error.
 407  */
 408 int mi_lttng_channels_open(struct mi_writer *writer);
 409
 410 /*
 411  * Machine interface of struct channel.
 412  *
 413  * writer An instance of a machine interface writer.
 414  * channel An instance of a channel.
 415  *
 416  * is_open Defines whether or not the session element shall be closed.
 417  *         This should be used carefully and the client
 418  *         must close the channel element.
 419  *         Use case: nested addition information on a channel.
 420  *                  ex: channel event.
 421  *
 422  * Returns zero if the element's value could be written.
 423  * Negative values indicate an error.
 424  */
 425 int mi_lttng_channel(struct mi_writer *writer,
 426                 struct lttng_channel *channel, int is_open);
 427
 428 /*
 429  * Machine interface of struct channel_attr.
 430  *
 431  * writer An instance of a machine interface writer.
 432  * attr An instance of a channel_attr struct.
 433  *
 434  * Returns zero if the element's value could be written.
 435  * Negative values indicate an error.
 436  */
 437 int mi_lttng_channel_attr(struct mi_writer *writer,
 438                 struct lttng_channel_attr *attr);
 439
 440 /*
 441 * Machine interface for event common attributes.
 442 *
 443 * writer An instance of a mi writer.
 444 * event single trace event.
 445 *
 446 * The common attribute are:
 447 * - mi event element
 448 * - event name
 449 * - event type
 450 * - enabled tag
 451 * - event filter
 452 *
 453 * Returns zero if the element's value could be written.
 454 * Negative values indicate an error.
 455 */
 456 int mi_lttng_event_common_attributes(struct mi_writer *writer,
 457                 struct lttng_event *event);
 458
 459 /*
 460  * Machine interface for kernel tracepoint event with a loglevel.
 461  *
 462  * writer An instance of a mi writer.
 463  * event single trace event.
 464  * domain Event's domain
 465  *
 466  * Returns zero if the element's value could be written.
 467  * Negative values indicate an error.
 468  */
 469 int mi_lttng_event_tracepoint_loglevel(struct mi_writer *writer,
 470                 struct lttng_event *event, enum lttng_domain_type domain);
 471
 472 /*
 473  * Machine interface for kernel tracepoint event with no loglevel.
 474  *
 475  * writer An instance of a mi writer.
 476  * event single trace event.
 477  *
 478  * Returns zero if the element's value could be written.
 479  * Negative values indicate an error.
 480  */
 481 int mi_lttng_event_tracepoint_no_loglevel(struct mi_writer *writer,
 482                 struct lttng_event *event);
 483
 484 /*
 485  * Machine interface for kernel function and probe event.
 486  *
 487  * writer An instance of a mi writer.
 488  * event single trace event.
 489  *
 490  * Returns zero if the element's value could be written.
 491  * Negative values indicate an error.
 492  */
 493 int mi_lttng_event_function_probe(struct mi_writer *writer,
 494                 struct lttng_event *event);
 495
 496 /*
 497  * Machine interface for kernel function entry event.
 498  *
 499  * writer An instance of a mi writer.
 500  * event single trace event.
 501  *
 502  * Returns zero if the element's value could be written.
 503  * Negative values indicate an error.
 504  */
 505 int mi_lttng_event_function_entry(struct mi_writer *writer,
 506                 struct lttng_event *event);
 507
 508 /*
 509  * Machine interface: open an events element.
 510  *
 511  * writer An instance of a machine interface writer.
 512  *
 513  * Returns zero if the element's value could be written.
 514  * Negative values indicate an error.
 515  */
 516 int mi_lttng_events_open(struct mi_writer *writer);
 517
 518 /*
 519  * Machine interface for printing an event.
 520  * The trace event type currently supported are:
 521  *  TRACEPOINT,
 522  *  PROBE,
 523  *  FUNCTION,
 524  *  FUNCTION_ENTRY,
 525  *  SYSCALL
 526  *
 527  * writer An instance of a mi writer.
 528  * event single trace event.
 529  * is_open Defines whether or not the session element shall be closed.
 530  *         This should be used carefully and the client
 531  *         must close the event element.
 532  *         Use case: nested additional information
 533  * domain Event's domain
 534  *
 535  * Returns zero if the element's value could be written.
 536  * Negative values indicate an error.
 537  */
 538 int mi_lttng_event(struct mi_writer *writer, struct lttng_event *event,
 539                 int is_open, enum lttng_domain_type domain);
 540
 541 /*
 542  * Machine interface for struct lttng_event_field.
 543  *
 544  * writer An instance of a mi writer.
 545  * field An event_field instance.
 546  *
 547  * Returns zero if the element's value could be written.
 548  * Negative values indicate an error.
 549  */
 550 int mi_lttng_event_field(struct mi_writer *writer,
 551                 struct lttng_event_field *field);
 552
 553 /*
 554  * Machine interface: open a event_fields element.
 555  *
 556  * writer An instance of a machine interface writer.
 557  *
 558  * Returns zero if the element have be written.
 559  * Negative values indicate an error.
 560  */
 561 int mi_lttng_event_fields_open(struct mi_writer *writer);
 562
 563 /*
 564  * Machine interface: open a trackers element.
 565  *
 566  * writer An instance of a machine interface writer.
 567  *
 568  * Returns zero if the element's value could be written.
 569  * Negative values indicate an error.
 570  */
 571 int mi_lttng_trackers_open(struct mi_writer *writer);
 572
 573 /*
 574  * Machine interface: open a pid_tracker element.
 575  *
 576  * writer An instance of a machine interface writer.
 577  *
 578  * Returns zero if the element's value could be written.
 579  * Negative values indicate an error.
 580  *
 581  * Note: A targets element is also opened for each tracker definition
 582  */
 583 int mi_lttng_pid_tracker_open(struct mi_writer *writer);
 584
 585 /*
 586  * Machine interface: open a PIDs element.
 587  *
 588  * writer An instance of a machine interface writer.
 589  *
 590  * Returns zero if the element's value could be written.
 591  * Negative values indicate an error.
 592  */
 593 int mi_lttng_pids_open(struct mi_writer *writer);
 594
 595 /*
 596  * Machine interface: open a processes element.
 597  *
 598  * writer An instance of a machine interface writer.
 599  *
 600  * Returns zero if the element's value could be written.
 601  * Negative values indicate an error.
 602  */
 603 int mi_lttng_processes_open(struct mi_writer *writer);
 604
 605 /*
 606  * Machine interface of a Process.
 607  *
 608  * writer An instance of a machine interface writer.
 609  * pid A PID.
 610  *
 611  * is_open Defines whether or not the session element shall be closed.
 612  *         This should be used carefully and the client
 613  *         must close the pid element.
 614  *         Use case: nested addition information on a domain
 615  *                  ex: channel event.
 616  *
 617  * Returns zero if the element's value could be written.
 618  * Negative values indicate an error.
 619  */
 620 int mi_lttng_process(struct mi_writer *writer, pid_t pid , const char *name,
 621                 int is_open);
 622
 623 /*
 624  * TODO: move pid of lttng list -u to process semantic on mi api bump
 625  * Machine interface of a Process.
 626  *
 627  * writer An instance of a machine interface writer.
 628  * pid A PID.
 629  *
 630  * is_open Defines whether or not the session element shall be closed.
 631  *         This should be used carefully and the client
 632  *         must close the pid element.
 633  *         Use case: nested addition information on a domain
 634  *                  ex: channel event.
 635  *
 636  * Returns zero if the element's value could be written.
 637  * Negative values indicate an error.
 638  */
 639 int mi_lttng_pid(struct mi_writer *writer, pid_t pid , const char *name,
 640                 int is_open);
 641 /*
 642  * Machine interface: open a targets element.
 643  *
 644  * writer An instance of a machine interface writer.
 645  *
 646  * Returns zero if the element's value could be written.
 647  * Negative values indicate an error.
 648  */
 649 int mi_lttng_targets_open(struct mi_writer *writer);
 650
 651 /*
 652  * Machine interface for track/untrack a pid_target
 653  *
 654  * writer An instance of a machine interface writer.
 655  *
 656  * Returns zero if the element's value could be written.
 657  * Negative values indicate an error.
 658  */
 659 int mi_lttng_pid_target(struct mi_writer *writer, pid_t pid, int is_open);
 660
 661 /*
 662  * Machine interface of a context.
 663  *
 664  * writer An instance of a machine interface writer
 665  *
 666  * context An instance of a lttng_event_context
 667  *
 668  * is_open Define if we close the context element
 669  *         This should be used carefully and the client
 670  *         need to close the context element.
 671  * Returns zero if the element's value could be written.
 672  * Negative values indicate an error.
 673  */
 674 int mi_lttng_context(struct mi_writer *writer,
 675                 struct lttng_event_context *context, int is_open);
 676
 677 /*
 678  * Machine interface of a perf_counter_context.
 679  *
 680  * writer An instance of a machine interface writer
 681  *
 682  * contest An instance of a lttng_event_perf_counter_ctx
 683  *
 684  * Returns zero if the element's value could be written.
 685  * Negative values indicate an error.
 686  */
 687 int mi_lttng_perf_counter_context(struct mi_writer *writer,
 688                 struct lttng_event_perf_counter_ctx  *perf_context);
 689
 690 /*
 691  * Machine interface of the snapshot list_output.
 692  * It specifies the session for which we are listing snapshots,
 693  * and it opens a snapshots element to list a sequence
 694  * of snapshots.
 695  *
 696  * writer An instance of a machine interface writer.
 697  *
 698  * session_name: Snapshot output for session "session_name".
 699  *
 700  * Note: The client has to close the session and the snapshots elements after
 701  * having listed every lttng_snapshot_output.
 702  *
 703  * Returns zero if the element's value could be written.
 704  * Negative values indicate an error.
 705  */
 706 int mi_lttng_snapshot_output_session_name(struct mi_writer *writer,
 707                 const char *session_name);
 708
 709 /*
 710  * Machine interface of the snapshot output.
 711  * The machine interface serializes the following attributes:
 712  * - id: ID of the snapshot output.
 713  * - name: Name of the output.
 714  * - data_url : Destination of the output.
 715  * - ctrl_url: Destination of the output.
 716  * - max_size: total size of all stream combined.
 717  *
 718  * writer An instance of a machine interface writer.
 719  *
 720  * output: A list of snapshot_output.
 721  *
 722  * Returns zero if the element's value could be written.
 723  * Negative values indicate an error.
 724  */
 725 int mi_lttng_snapshot_list_output(struct mi_writer *writer,
 726                 struct lttng_snapshot_output *output);
 727
 728 /*
 729  * Machine interface of the output of the command snapshot del output
 730  * when deleting a snapshot either by id or by name.
 731  * If the snapshot was found and successfully deleted using its id,
 732  * it return the id of the snapshot and the current session name on which it
 733  * was attached.
 734  *
 735  * Otherwise, it do the same process with the name of the snapshot, if the
 736  * snapshot output id is undefined.
 737  *
 738  * writer An instance of a machine interface writer.
 739  *
 740  * id: ID of the snapshot output.
 741  *
 742  * name: Name of the snapshot.
 743  *
 744  * current_session_name: Session to which the snapshot belongs.
 745  *
 746  * Returns zero if the element's value could be written.
 747  * Negative values indicate an error.
 748  */
 749 int mi_lttng_snapshot_del_output(struct mi_writer *writer, int id,
 750                 const char *name, const char *current_session_name);
 751
 752 /*
 753  * Machine interface of the output of the command snapshot add output
 754  * when adding a snapshot from a user URL.
 755  *
 756  * If the snapshot was successfully added, the machine interface lists
 757  * these information:
 758  * - id: ID of the newly add snapshot output.
 759  * - current_session_name: Name of the session to which the output was added.
 760  * - ctrl_url: Destination of the output.
 761  * - max_size: total size of all stream combined.
 762  *
 763  * writer An instance of a machine interface writer.
 764  *
 765  * current_session_name: Session to which the snapshot belongs.
 766  *
 767  * n_ptr:
 768  *
 769  * output: iterator over a lttng_snapshot_output_list which contain
 770  * the snapshot output informations.
 771  *
 772  * Returns zero if the element's value could be written.
 773  * Negative values indicate an error.
 774  */
 775 int mi_lttng_snapshot_add_output(struct mi_writer *writer,
 776                 const char *current_session_name, const char *n_ptr,
 777                 struct lttng_snapshot_output *output);
 778
 779 /*
 780  * Machine interface of the output of the command snapshot
 781  * record  from a URL (if given).
 782  *
 783  * If the snapshot is successfully recorded from a url, the machine interface
 784  * output the following information:
 785  * - url: Destination of the output stored in the snapshot.
 786  *
 787  * Otherwise, the machine interface output the data and ctrl url received
 788  * from the command-line.
 789  *
 790  * writer An instance of a machine interface writer.
 791  *
 792  * current_session_name: Snapshot record for session "current_session_name".
 793  *
 794  * ctrl_url, data_url: Destination of the output receive from the command-line.
 795  *
 796  * Returns zero if the element's value could be written.
 797  * Negative values indicate an error.
 798  */
 799 int mi_lttng_snapshot_record(struct mi_writer *writer,
 800                 const char *current_session_name, const char *url,
 801                 const char *cmdline_ctrl_url, const char *cmdline_data_url);
 802
 803 #endif /* _MI_LTTNG_H */