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
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #ifndef _LTTNG_H
  24 #define _LTTNG_H
  25
  26 #include <limits.h>
  27 #include <stdint.h>
  28 #include <sys/types.h>
  29
  30 /*
  31  * Event symbol length. Copied from LTTng kernel ABI.
  32  */
  33 #define LTTNG_SYMBOL_NAME_LEN 256
  34
  35 /*
  36  * Every lttng_event_* structure both apply to kernel event and user-space
  37  * event.
  38  */
  39
  40 /*
  41  * Domain type are the different possible tracers.
  42  */
  43 enum lttng_domain_type {
  44         LTTNG_DOMAIN_KERNEL                   = 1,
  45         LTTNG_DOMAIN_UST                      = 2,
  46
  47         /*
  48          * For now, the domains below are not implemented. However, we keep them
  49          * here in order to retain their enum values for future development. Note
  50          * that it is on the roadmap to implement them.
  51          *
  52         LTTNG_DOMAIN_UST_EXEC_NAME            = 3,
  53         LTTNG_DOMAIN_UST_PID                  = 4,
  54         LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN  = 5,
  55         */
  56 };
  57
  58 /*
  59  * Instrumentation type of tracing event.
  60  */
  61 enum lttng_event_type {
  62         LTTNG_EVENT_ALL                       = -1,
  63         LTTNG_EVENT_TRACEPOINT                = 0,
  64         LTTNG_EVENT_PROBE                     = 1,
  65         LTTNG_EVENT_FUNCTION                  = 2,
  66         LTTNG_EVENT_FUNCTION_ENTRY            = 3,
  67         LTTNG_EVENT_NOOP                      = 4,
  68         LTTNG_EVENT_SYSCALL                   = 5,
  69 };
  70
  71 /*
  72  * Loglevel information.
  73  */
  74 enum lttng_loglevel_type {
  75         LTTNG_EVENT_LOGLEVEL                  = 0,
  76         LTTNG_EVENT_LOGLEVEL_ONLY             = 1,
  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 struct lttng_domain {
 107         enum lttng_domain_type type;
 108         union {
 109                 pid_t pid;
 110                 char exec_name[NAME_MAX];
 111         } attr;
 112 };
 113
 114 /* Perf counter attributes */
 115 struct lttng_event_perf_counter_ctx {
 116         uint32_t type;
 117         uint64_t config;
 118         char name[LTTNG_SYMBOL_NAME_LEN];
 119 };
 120
 121 /* Event/Channel context */
 122 struct lttng_event_context {
 123         enum lttng_event_context_type ctx;
 124         union {
 125                 struct lttng_event_perf_counter_ctx perf_counter;
 126         } u;
 127 };
 128
 129 /*
 130  * Event probe.
 131  *
 132  * Either addr is used or symbol_name and offset.
 133  */
 134 struct lttng_event_probe_attr {
 135         uint64_t addr;
 136
 137         uint64_t offset;
 138         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 139 };
 140
 141 /*
 142  * Function tracer
 143  */
 144 struct lttng_event_function_attr {
 145         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 146 };
 147
 148 /*
 149  * Generic lttng event
 150  */
 151 struct lttng_event {
 152         enum lttng_event_type type;
 153         char name[LTTNG_SYMBOL_NAME_LEN];
 154
 155         enum lttng_loglevel_type loglevel_type;
 156         char loglevel[LTTNG_SYMBOL_NAME_LEN];
 157         int64_t loglevel_value;         /* for printing */
 158
 159         uint32_t enabled;
 160         pid_t pid;
 161         /* Per event type configuration */
 162         union {
 163                 struct lttng_event_probe_attr probe;
 164                 struct lttng_event_function_attr ftrace;
 165         } attr;
 166 };
 167
 168 /*
 169  * Tracer channel attributes. For both kernel and user-space.
 170  */
 171 struct lttng_channel_attr {
 172         int overwrite;                      /* 1: overwrite, 0: discard */
 173         uint64_t subbuf_size;               /* bytes */
 174         uint64_t num_subbuf;                /* power of 2 */
 175         unsigned int switch_timer_interval; /* usec */
 176         unsigned int read_timer_interval;   /* usec */
 177         enum lttng_event_output output;     /* splice, mmap */
 178 };
 179
 180 /*
 181  * Channel information structure. For both kernel and user-space.
 182  */
 183 struct lttng_channel {
 184         char name[LTTNG_SYMBOL_NAME_LEN];
 185         uint32_t enabled;
 186         struct lttng_channel_attr attr;
 187 };
 188
 189 struct lttng_calibrate {
 190         enum lttng_calibrate_type type;
 191 };
 192
 193 /*
 194  * Basic session information.
 195  *
 196  * This is an 'output data' meaning that it only comes *from* the session
 197  * daemon *to* the lttng client. It's basically a 'human' representation of
 198  * tracing entities (here a session).
 199  */
 200 struct lttng_session {
 201         char name[NAME_MAX];
 202         /* The path where traces are written */
 203         char path[PATH_MAX];
 204         uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
 205 };
 206
 207 /*
 208  * Handle used as a context for commands.
 209  */
 210 struct lttng_handle {
 211         char session_name[NAME_MAX];
 212         struct lttng_domain domain;
 213 };
 214
 215 /*
 216  * Public LTTng control API
 217  *
 218  * For functions having a lttng domain type as parameter, if a bad value is
 219  * given, NO default is applied and an error is returned.
 220  *
 221  * On success, all functions of the API return 0 or the size of the allocated
 222  * array.
 223  *
 224  * On error, a negative value is returned being a specific lttng-tools error
 225  * code which can be humanly interpreted with lttng_strerror(err).
 226  */
 227
 228 /*
 229  * Create an handle used as a context for every request made to the library.
 230  *
 231  * This handle contains the session name and lttng domain on which the command
 232  * will be executed on.
 233  */
 234 extern struct lttng_handle *lttng_create_handle(const char *session_name,
 235                 struct lttng_domain *domain);
 236
 237 /*
 238  * Destroy an handle. This will simply free(3) the data pointer returned by
 239  * lttng_create_handle() and rendering it unsuable.
 240  */
 241 extern void lttng_destroy_handle(struct lttng_handle *handle);
 242
 243 /*
 244  * Create tracing session using a name and a path where trace will be written.
 245  */
 246 extern int lttng_create_session(const char *name, const char *path);
 247
 248 /*
 249  * Destroy tracing session.
 250  *
 251  * The session will not be useable anymore, tracing will stopped for all
 252  * registered trace and tracing buffers will be flushed.
 253  */
 254 extern int lttng_destroy_session(const char *name);
 255
 256 /*
 257  * List all tracing sessions.
 258  *
 259  * Return the size of the "lttng_session" array. Caller must free(3).
 260  */
 261 extern int lttng_list_sessions(struct lttng_session **sessions);
 262
 263 /*
 264  * List registered domain(s) of a session.
 265  *
 266  * Return the size of the "lttng_domain" array. Caller must free(3).
 267  */
 268 extern int lttng_list_domains(const char *session_name,
 269                 struct lttng_domain **domains);
 270
 271 /*
 272  * List channel(s) of a session.
 273  *
 274  * Return the size of the "lttng_channel" array. Caller must free(3).
 275  */
 276 extern int lttng_list_channels(struct lttng_handle *handle,
 277                 struct lttng_channel **channels);
 278
 279 /*
 280  * List event(s) of a session channel.
 281  *
 282  * Return the size of the "lttng_event" array. Caller must free(3).
 283  */
 284 extern int lttng_list_events(struct lttng_handle *handle,
 285                 const char *channel_name, struct lttng_event **events);
 286
 287 /*
 288  * List available tracepoints of a specific lttng domain.
 289  *
 290  * Return the size of the "lttng_event" array. Caller must free(3).
 291  */
 292 extern int lttng_list_tracepoints(struct lttng_handle *handle,
 293                 struct lttng_event **events);
 294
 295 /*
 296  * Check if a session daemon is alive.
 297  */
 298 extern int lttng_session_daemon_alive(void);
 299
 300 /*
 301  * Set tracing group for the *current* flow of execution.
 302  */
 303 extern int lttng_set_tracing_group(const char *name);
 304
 305 /*
 306  * Return a human readable error message of a lttng-tools error code.
 307  *
 308  * Parameter MUST be a negative value or else you'll get a generic message.
 309  */
 310 extern const char *lttng_strerror(int code);
 311
 312 /*
 313  * This call permits to register an "outside consumer" to a session and a lttng
 314  * domain. No consumer will be spawned and all fds/commands will go through the
 315  * socket path given (socket_path).
 316  *
 317  * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 318  * command socket. The error socket is not supported yet for roaming consumers.
 319  */
 320 extern int lttng_register_consumer(struct lttng_handle *handle,
 321                 const char *socket_path);
 322
 323 /*
 324  * Start tracing for *all* registered trace (kernel and user-space).
 325  */
 326 extern int lttng_start_tracing(const char *session_name);
 327
 328 /*
 329  * Stop tracing for *all* registered trace (kernel and user-space).
 330  */
 331 extern int lttng_stop_tracing(const char *session_name);
 332
 333 /*
 334  * Add context to event for a specific channel.
 335  *
 336  * If event_name is NULL, the context is applied to all event of the channel.
 337  * If channel_name is NULL, a lookup of the event's channel is done.
 338  * If both are NULL, the context is applied on all events of all channels.
 339  */
 340 extern int lttng_add_context(struct lttng_handle *handle,
 341                 struct lttng_event_context *ctx, const char *event_name,
 342                 const char *channel_name);
 343
 344 /*
 345  * Create or enable a kernel event.
 346  *
 347  * If the event you are trying to enable does not exist, it will be created,
 348  * else it is enabled.
 349  *
 350  * If channel_name is NULL, the default channel is used (channel0).
 351  */
 352 extern int lttng_enable_event(struct lttng_handle *handle,
 353                 struct lttng_event *ev, const char *channel_name);
 354
 355 /*
 356  * Create or enable a kernel channel.
 357  *
 358  * If name is NULL, the default channel is enabled (channel0).
 359  */
 360 extern int lttng_enable_channel(struct lttng_handle *handle,
 361                 struct lttng_channel *chan);
 362
 363 /*
 364  * Disable kernel event.
 365  *
 366  * If channel_name is NULL, the default channel is used (channel0).
 367  */
 368 extern int lttng_disable_event(struct lttng_handle *handle,
 369                 const char *name, const char *channel_name);
 370
 371 /*
 372  * Disable kernel channel.
 373  *
 374  * If channel_name is NULL, the default channel is disabled (channel0).
 375  */
 376 extern int lttng_disable_channel(struct lttng_handle *handle,
 377                 const char *name);
 378
 379 /*
 380  * Calibrate LTTng overhead.
 381  */
 382 extern int lttng_calibrate(struct lttng_handle *handle,
 383                 struct lttng_calibrate *calibrate);
 384
 385 /*
 386  * Set the default channel attributes for a specific domain and an allocated
 387  * lttng_channel_attr pointer.
 388  */
 389 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 390                 struct lttng_channel_attr *attr);
 391
 392 #endif /* _LTTNG_H */