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 as published by the
  10  * Free Software Foundation; only version 2.1 of the License.
  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 #include <limits.h>
  26 #include <stdint.h>
  27 #include <sys/types.h>
  28
  29 /*
  30  * Event symbol length. Copied from LTTng kernel ABI.
  31  */
  32 #define LTTNG_SYMBOL_NAME_LEN             256
  33
  34 /*
  35  * Every lttng_event_* structure both apply to kernel event and user-space
  36  * event.
  37  */
  38
  39 /*
  40  * Domain types: the different possible tracers.
  41  */
  42 enum lttng_domain_type {
  43         LTTNG_DOMAIN_KERNEL                   = 1,
  44         LTTNG_DOMAIN_UST                      = 2,
  45
  46         /*
  47          * For now, the domains below are not implemented. However, we keep them
  48          * here in order to retain their enum values for future development. Note
  49          * that it is on the roadmap to implement them.
  50          *
  51         LTTNG_DOMAIN_UST_EXEC_NAME            = 3,
  52         LTTNG_DOMAIN_UST_PID                  = 4,
  53         LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN  = 5,
  54         */
  55 };
  56
  57 /*
  58  * Instrumentation type of tracing event.
  59  */
  60 enum lttng_event_type {
  61         LTTNG_EVENT_ALL                       = -1,
  62         LTTNG_EVENT_TRACEPOINT                = 0,
  63         LTTNG_EVENT_PROBE                     = 1,
  64         LTTNG_EVENT_FUNCTION                  = 2,
  65         LTTNG_EVENT_FUNCTION_ENTRY            = 3,
  66         LTTNG_EVENT_NOOP                      = 4,
  67         LTTNG_EVENT_SYSCALL                   = 5,
  68 };
  69
  70 /*
  71  * Loglevel information.
  72  */
  73 enum lttng_loglevel_type {
  74         LTTNG_EVENT_LOGLEVEL_ALL              = 0,
  75         LTTNG_EVENT_LOGLEVEL_RANGE            = 1,
  76         LTTNG_EVENT_LOGLEVEL_SINGLE           = 2,
  77 };
  78
  79 /*
  80  * LTTng consumer mode
  81  */
  82 enum lttng_event_output {
  83         LTTNG_EVENT_SPLICE                    = 0,
  84         LTTNG_EVENT_MMAP                      = 1,
  85 };
  86
  87 /* Event context possible type */
  88 enum lttng_event_context_type {
  89         LTTNG_EVENT_CONTEXT_PID               = 0,
  90         LTTNG_EVENT_CONTEXT_PERF_COUNTER      = 1,
  91         LTTNG_EVENT_CONTEXT_PROCNAME          = 2,
  92         LTTNG_EVENT_CONTEXT_PRIO              = 3,
  93         LTTNG_EVENT_CONTEXT_NICE              = 4,
  94         LTTNG_EVENT_CONTEXT_VPID              = 5,
  95         LTTNG_EVENT_CONTEXT_TID               = 6,
  96         LTTNG_EVENT_CONTEXT_VTID              = 7,
  97         LTTNG_EVENT_CONTEXT_PPID              = 8,
  98         LTTNG_EVENT_CONTEXT_VPPID             = 9,
  99         LTTNG_EVENT_CONTEXT_PTHREAD_ID        = 10,
 100 };
 101
 102 enum lttng_calibrate_type {
 103         LTTNG_CALIBRATE_FUNCTION              = 0,
 104 };
 105
 106 #define LTTNG_DOMAIN_PADDING1              16
 107 #define LTTNG_DOMAIN_PADDING2              LTTNG_SYMBOL_NAME_LEN + 32
 108 struct lttng_domain {
 109         enum lttng_domain_type type;
 110         char padding[LTTNG_DOMAIN_PADDING1];
 111
 112         union {
 113                 pid_t pid;
 114                 char exec_name[NAME_MAX];
 115                 char padding[LTTNG_DOMAIN_PADDING2];
 116         } attr;
 117 };
 118
 119 /* Perf counter attributes */
 120 #define LTTNG_PERF_EVENT_PADDING1          16
 121 struct lttng_event_perf_counter_ctx {
 122         uint32_t type;
 123         uint64_t config;
 124         char name[LTTNG_SYMBOL_NAME_LEN];
 125
 126         char padding[LTTNG_PERF_EVENT_PADDING1];
 127 };
 128
 129 /* Event/Channel context */
 130 #define LTTNG_EVENT_CONTEXT_PADDING1       16
 131 #define LTTNG_EVENT_CONTEXT_PADDING2       LTTNG_SYMBOL_NAME_LEN + 32
 132 struct lttng_event_context {
 133         enum lttng_event_context_type ctx;
 134         char padding[LTTNG_EVENT_CONTEXT_PADDING1];
 135
 136         union {
 137                 struct lttng_event_perf_counter_ctx perf_counter;
 138                 char padding[LTTNG_EVENT_CONTEXT_PADDING2];
 139         } u;
 140 };
 141
 142 /*
 143  * Event probe.
 144  *
 145  * Either addr is used or symbol_name and offset.
 146  */
 147 #define LTTNG_EVENT_PROBE_PADDING1         16
 148 struct lttng_event_probe_attr {
 149         uint64_t addr;
 150
 151         uint64_t offset;
 152         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 153
 154         char padding[LTTNG_EVENT_PROBE_PADDING1];
 155 };
 156
 157 /*
 158  * Function tracer
 159  */
 160 #define LTTNG_EVENT_FUNCTION_PADDING1      16
 161 struct lttng_event_function_attr {
 162         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 163
 164         char padding[LTTNG_EVENT_FUNCTION_PADDING1];
 165 };
 166
 167 /*
 168  * Generic lttng event
 169  */
 170 #define LTTNG_EVENT_PADDING1               16
 171 #define LTTNG_EVENT_PADDING2               LTTNG_SYMBOL_NAME_LEN + 32
 172 struct lttng_event {
 173         enum lttng_event_type type;
 174         char name[LTTNG_SYMBOL_NAME_LEN];
 175
 176         enum lttng_loglevel_type loglevel_type;
 177         int loglevel;
 178
 179         uint32_t enabled;
 180         pid_t pid;
 181
 182         char padding[LTTNG_EVENT_PADDING1];
 183
 184         /* Per event type configuration */
 185         union {
 186                 struct lttng_event_probe_attr probe;
 187                 struct lttng_event_function_attr ftrace;
 188
 189                 char padding[LTTNG_EVENT_PADDING2];
 190         } attr;
 191 };
 192
 193 /*
 194  * Tracer channel attributes. For both kernel and user-space.
 195  */
 196 #define LTTNG_CHANNEL_ATTR_PADDING1        LTTNG_SYMBOL_NAME_LEN + 32
 197 struct lttng_channel_attr {
 198         int overwrite;                      /* 1: overwrite, 0: discard */
 199         uint64_t subbuf_size;               /* bytes */
 200         uint64_t num_subbuf;                /* power of 2 */
 201         unsigned int switch_timer_interval; /* usec */
 202         unsigned int read_timer_interval;   /* usec */
 203         enum lttng_event_output output;     /* splice, mmap */
 204
 205         char padding[LTTNG_CHANNEL_ATTR_PADDING1];
 206 };
 207
 208 /*
 209  * Channel information structure. For both kernel and user-space.
 210  */
 211 #define LTTNG_CHANNEL_PADDING1             16
 212 struct lttng_channel {
 213         char name[LTTNG_SYMBOL_NAME_LEN];
 214         uint32_t enabled;
 215         struct lttng_channel_attr attr;
 216
 217         char padding[LTTNG_CHANNEL_PADDING1];
 218 };
 219
 220 #define LTTNG_CALIBRATE_PADDING1           16
 221 struct lttng_calibrate {
 222         enum lttng_calibrate_type type;
 223
 224         char padding[LTTNG_CALIBRATE_PADDING1];
 225 };
 226
 227 /*
 228  * Basic session information.
 229  *
 230  * This is an 'output data' meaning that it only comes *from* the session
 231  * daemon *to* the lttng client. It's basically a 'human' representation of
 232  * tracing entities (here a session).
 233  */
 234 #define LTTNG_SESSION_PADDING1             16
 235 struct lttng_session {
 236         char name[NAME_MAX];
 237         /* The path where traces are written */
 238         char path[PATH_MAX];
 239         uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
 240
 241         char padding[LTTNG_SESSION_PADDING1];
 242 };
 243
 244 /*
 245  * Handle used as a context for commands.
 246  */
 247 #define LTTNG_HANDLE_PADDING1              16
 248 struct lttng_handle {
 249         char session_name[NAME_MAX];
 250         struct lttng_domain domain;
 251
 252         char padding[LTTNG_HANDLE_PADDING1];
 253 };
 254
 255 /*
 256  * Public LTTng control API
 257  *
 258  * For functions having an lttng domain type as parameter, if a bad value is
 259  * given, NO default is applied and an error is returned.
 260  *
 261  * On success, all functions of the API return 0 or the size of the allocated
 262  * array (in bytes).
 263  *
 264  * On error, a negative value is returned being a specific lttng-tools error
 265  * code which can be humanly interpreted with lttng_strerror(err).
 266  *
 267  * Exceptions to this are noted below.
 268  */
 269
 270 /*
 271  * Create a handle used as a context for every request made to the library.
 272  *
 273  * This handle contains the session name and lttng domain on which the command
 274  * will be executed.
 275  * The returned pointer will be NULL in case of malloc() error.
 276  */
 277 extern struct lttng_handle *lttng_create_handle(const char *session_name,
 278                 struct lttng_domain *domain);
 279
 280 /*
 281  * Destroy a handle. This will simply free(3) the data pointer returned by
 282  * lttng_create_handle(), rendering it unusable.
 283  */
 284 extern void lttng_destroy_handle(struct lttng_handle *handle);
 285
 286 /*
 287  * Create a tracing session using a name and a path where the trace will be
 288  * written.
 289  */
 290 extern int lttng_create_session(const char *name, const char *path);
 291
 292 /*
 293  * Destroy a tracing session.
 294  *
 295  * The session will not be usable anymore, tracing will be stopped for all
 296  * registered traces, and the tracing buffers will be flushed.
 297  */
 298 extern int lttng_destroy_session(const char *name);
 299
 300 /*
 301  * List all the tracing sessions.
 302  *
 303  * Return the size (number of entries) of the "lttng_session" array. Caller
 304  * must free(3).
 305  */
 306 extern int lttng_list_sessions(struct lttng_session **sessions);
 307
 308 /*
 309  * List the registered domain(s) of a session.
 310  *
 311  * Return the size (number of entries) of the "lttng_domain" array. Caller
 312  * must free(3).
 313  */
 314 extern int lttng_list_domains(const char *session_name,
 315                 struct lttng_domain **domains);
 316
 317 /*
 318  * List the channel(s) of a session.
 319  *
 320  * Return the size (number of entries) of the "lttng_channel" array. Caller
 321  * must free(3).
 322  */
 323 extern int lttng_list_channels(struct lttng_handle *handle,
 324                 struct lttng_channel **channels);
 325
 326 /*
 327  * List the event(s) of a session channel.
 328  *
 329  * Return the size (number of entries) of the "lttng_event" array.
 330  * Caller must free(3).
 331  */
 332 extern int lttng_list_events(struct lttng_handle *handle,
 333                 const char *channel_name, struct lttng_event **events);
 334
 335 /*
 336  * List the available tracepoints of a specific lttng domain.
 337  *
 338  * Return the size (number of entries) of the "lttng_event" array.
 339  * Caller must free(3).
 340  */
 341 extern int lttng_list_tracepoints(struct lttng_handle *handle,
 342                 struct lttng_event **events);
 343
 344 /*
 345  * Check if a session daemon is alive.
 346  *
 347  * Return 1 if alive or 0 if not. On error returns a negative value.
 348  */
 349 extern int lttng_session_daemon_alive(void);
 350
 351 /*
 352  * Set the tracing group for the *current* flow of execution.
 353  *
 354  * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
 355  */
 356 extern int lttng_set_tracing_group(const char *name);
 357
 358 /*
 359  * Return a human-readable error message for an lttng-tools error code.
 360  *
 361  * Parameter MUST be a negative value or else you'll get a generic message.
 362  */
 363 extern const char *lttng_strerror(int code);
 364
 365 /*
 366  * This call registers an "outside consumer" for a session and an lttng domain.
 367  * No consumer will be spawned and all fds/commands will go through the socket
 368  * path given (socket_path).
 369  *
 370  * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 371  * command socket. The error socket is not supported yet for roaming consumers.
 372  */
 373 extern int lttng_register_consumer(struct lttng_handle *handle,
 374                 const char *socket_path);
 375
 376 /*
 377  * Start tracing for *all* registered traces (kernel and user-space).
 378  */
 379 extern int lttng_start_tracing(const char *session_name);
 380
 381 /*
 382  * Stop tracing for *all* registered traces (kernel and user-space).
 383  */
 384 extern int lttng_stop_tracing(const char *session_name);
 385
 386 /*
 387  * Add context to event(s) for a specific channel (or for all).
 388  *
 389  * If event_name is NULL, the context is applied to all events of the channel.
 390  * If channel_name is NULL, a lookup of the event's channel is done.
 391  * If both are NULL, the context is applied to all events of all channels.
 392  */
 393 extern int lttng_add_context(struct lttng_handle *handle,
 394                 struct lttng_event_context *ctx, const char *event_name,
 395                 const char *channel_name);
 396
 397 /*
 398  * Create or enable a kernel event (or events) for a channel.
 399  *
 400  * If the event you are trying to enable does not exist, it will be created,
 401  * else it is enabled.
 402  * If event_name is NULL, all events are enabled.
 403  * If channel_name is NULL, the default channel is used (channel0).
 404  */
 405 extern int lttng_enable_event(struct lttng_handle *handle,
 406                 struct lttng_event *ev, const char *channel_name);
 407
 408 /*
 409  * Create or enable a kernel channel.
 410  * The channel name cannot be NULL.
 411  */
 412 extern int lttng_enable_channel(struct lttng_handle *handle,
 413                 struct lttng_channel *chan);
 414
 415 /*
 416  * Disable kernel event(s) of a channel and domain.
 417  *
 418  * If event_name is NULL, all events are disabled.
 419  * If channel_name is NULL, the default channel is used (channel0).
 420  */
 421 extern int lttng_disable_event(struct lttng_handle *handle,
 422                 const char *name, const char *channel_name);
 423
 424 /*
 425  * Disable kernel channel.
 426  *
 427  * The channel name cannot be NULL.
 428  */
 429 extern int lttng_disable_channel(struct lttng_handle *handle,
 430                 const char *name);
 431
 432 /*
 433  * Calibrate LTTng overhead.
 434  */
 435 extern int lttng_calibrate(struct lttng_handle *handle,
 436                 struct lttng_calibrate *calibrate);
 437
 438 /*
 439  * Set the default channel attributes for a specific domain and an allocated
 440  * lttng_channel_attr pointer.
 441  *
 442  * If either or both of the arguments are NULL, nothing happens.
 443  */
 444 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 445                 struct lttng_channel_attr *attr);
 446
 447 #endif /* _LTTNG_H */