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 /* Default unix group name for tracing. */
  31 #define LTTNG_DEFAULT_TRACING_GROUP "tracing"
  32
  33 /* Environment variable to set session daemon binary path. */
  34 #define LTTNG_SESSIOND_PATH_ENV "LTTNG_SESSIOND_PATH"
  35
  36 /* Default trace output directory name */
  37 #define LTTNG_DEFAULT_TRACE_DIR_NAME "lttng-traces"
  38
  39 /*
  40  * Event symbol length. Copied from LTTng kernel ABI.
  41  */
  42 #define LTTNG_SYMBOL_NAME_LEN 256
  43
  44 /*
  45  * Every lttng_event_* structure both apply to kernel event and user-space
  46  * event.
  47  */
  48
  49 /*
  50  * Domain type are the different possible tracers.
  51  */
  52 enum lttng_domain_type {
  53         LTTNG_DOMAIN_KERNEL                   = 1,
  54         LTTNG_DOMAIN_UST                      = 2,
  55         LTTNG_DOMAIN_UST_EXEC_NAME            = 3,
  56         LTTNG_DOMAIN_UST_PID                  = 4,
  57         LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN  = 5,
  58 };
  59
  60 /*
  61  * Instrumentation type of tracing event.
  62  */
  63 enum lttng_event_type {
  64         LTTNG_EVENT_ALL                       = -1,
  65         LTTNG_EVENT_TRACEPOINT                = 0,
  66         LTTNG_EVENT_PROBE                     = 1,
  67         LTTNG_EVENT_FUNCTION                  = 2,
  68         LTTNG_EVENT_FUNCTION_ENTRY            = 3,
  69         LTTNG_EVENT_NOOP                      = 4,
  70         LTTNG_EVENT_SYSCALL                   = 5,
  71         LTTNG_EVENT_TRACEPOINT_LOGLEVEL       = 6,
  72 };
  73
  74 /*
  75  * LTTng consumer mode
  76  */
  77 enum lttng_event_output {
  78         LTTNG_EVENT_SPLICE = 0,
  79         LTTNG_EVENT_MMAP   = 1,
  80 };
  81
  82 /* Event context possible type */
  83 enum lttng_event_context_type {
  84         LTTNG_EVENT_CONTEXT_PID                = 0,
  85         LTTNG_EVENT_CONTEXT_PERF_COUNTER       = 1,
  86         LTTNG_EVENT_CONTEXT_COMM               = 2,
  87         LTTNG_EVENT_CONTEXT_PRIO               = 3,
  88         LTTNG_EVENT_CONTEXT_NICE               = 4,
  89         LTTNG_EVENT_CONTEXT_VPID               = 5,
  90         LTTNG_EVENT_CONTEXT_TID                = 6,
  91         LTTNG_EVENT_CONTEXT_VTID               = 7,
  92         LTTNG_EVENT_CONTEXT_PPID               = 8,
  93         LTTNG_EVENT_CONTEXT_VPPID              = 9,
  94 };
  95
  96 enum lttng_calibrate_type {
  97         LTTNG_CALIBRATE_FUNCTION               = 0,
  98 };
  99
 100 struct lttng_domain {
 101         enum lttng_domain_type type;
 102         union {
 103                 pid_t pid;
 104                 char exec_name[NAME_MAX];
 105         } attr;
 106 };
 107
 108 /* Perf counter attributes */
 109 struct lttng_event_perf_counter_ctx {
 110         uint32_t type;
 111         uint64_t config;
 112         char name[LTTNG_SYMBOL_NAME_LEN];
 113 };
 114
 115 /* Event/Channel context */
 116 struct lttng_event_context {
 117         enum lttng_event_context_type ctx;
 118         union {
 119                 struct lttng_event_perf_counter_ctx perf_counter;
 120         } u;
 121 };
 122
 123 /*
 124  * Event probe.
 125  *
 126  * Either addr is used or symbol_name and offset.
 127  */
 128 struct lttng_event_probe_attr {
 129         uint64_t addr;
 130
 131         uint64_t offset;
 132         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 133 };
 134
 135 /*
 136  * Function tracer
 137  */
 138 struct lttng_event_function_attr {
 139         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 140 };
 141
 142 /*
 143  * Generic lttng event
 144  */
 145 struct lttng_event {
 146         char name[LTTNG_SYMBOL_NAME_LEN];
 147         char loglevel[LTTNG_SYMBOL_NAME_LEN];
 148         int64_t loglevel_value;
 149         enum lttng_event_type type;
 150         uint32_t enabled;
 151         pid_t pid;
 152         /* Per event type configuration */
 153         union {
 154                 struct lttng_event_probe_attr probe;
 155                 struct lttng_event_function_attr ftrace;
 156         } attr;
 157 };
 158
 159 /*
 160  * Tracer channel attributes. For both kernel and user-space.
 161  */
 162 struct lttng_channel_attr {
 163         int overwrite;                      /* 1: overwrite, 0: discard */
 164         uint64_t subbuf_size;               /* bytes */
 165         uint64_t num_subbuf;                /* power of 2 */
 166         unsigned int switch_timer_interval; /* usec */
 167         unsigned int read_timer_interval;   /* usec */
 168         enum lttng_event_output output;     /* splice, mmap */
 169 };
 170
 171 /*
 172  * Channel information structure. For both kernel and user-space.
 173  */
 174 struct lttng_channel {
 175         char name[NAME_MAX];
 176         uint32_t enabled;
 177         struct lttng_channel_attr attr;
 178 };
 179
 180 struct lttng_calibrate {
 181         enum lttng_calibrate_type type;
 182 };
 183
 184 /*
 185  * Basic session information.
 186  *
 187  * This is an 'output data' meaning that it only comes *from* the session
 188  * daemon *to* the lttng client. It's basically a 'human' representation of
 189  * tracing entities (here a session).
 190  */
 191 struct lttng_session {
 192         char name[NAME_MAX];
 193         /* The path where traces are written */
 194         char path[PATH_MAX];
 195         uint32_t enabled;       /* enabled/started: 1, disabled/stopped: 0 */
 196 };
 197
 198 /*
 199  * Handle used as a context for commands.
 200  */
 201 struct lttng_handle {
 202         char session_name[NAME_MAX];
 203         struct lttng_domain domain;
 204 };
 205
 206 /*
 207  * Public LTTng control API
 208  *
 209  * For functions having a lttng domain type as parameter, if a bad value is
 210  * given, NO default is applied and an error is returned.
 211  *
 212  * On success, all functions of the API return 0 or the size of the allocated
 213  * array.
 214  *
 215  * On error, a negative value is returned being a specific lttng-tools error
 216  * code which can be humanly interpreted with lttng_strerror(err).
 217  */
 218
 219 /*
 220  * Create an handle used as a context for every request made to the library.
 221  *
 222  * This handle contains the session name and lttng domain on which the command
 223  * will be executed on.
 224  */
 225 extern struct lttng_handle *lttng_create_handle(const char *session_name,
 226                 struct lttng_domain *domain);
 227
 228 /*
 229  * Destroy an handle. This will simply free(3) the data pointer returned by
 230  * lttng_create_handle() and rendering it unsuable.
 231  */
 232 extern void lttng_destroy_handle(struct lttng_handle *handle);
 233
 234 /*
 235  * Create tracing session using a name and a path where trace will be written.
 236  */
 237 extern int lttng_create_session(const char *name, const char *path);
 238
 239 /*
 240  * Destroy tracing session.
 241  *
 242  * The session will not be useable anymore, tracing will stopped for all
 243  * registered trace and tracing buffers will be flushed.
 244  */
 245 extern int lttng_destroy_session(struct lttng_handle *handle);
 246
 247 /*
 248  * List all tracing sessions.
 249  *
 250  * Return the size of the "lttng_session" array. Caller must free(3).
 251  */
 252 extern int lttng_list_sessions(struct lttng_session **sessions);
 253
 254 /*
 255  * List registered domain(s) of a session.
 256  *
 257  * Return the size of the "lttng_domain" array. Caller must free(3).
 258  */
 259 extern int lttng_list_domains(struct lttng_handle *handle,
 260                 struct lttng_domain **domains);
 261
 262 /*
 263  * List channel(s) of a session.
 264  *
 265  * Return the size of the "lttng_channel" array. Caller must free(3).
 266  */
 267 extern int lttng_list_channels(struct lttng_handle *handle,
 268                 struct lttng_channel **channels);
 269
 270 /*
 271  * List event(s) of a session channel.
 272  *
 273  * Return the size of the "lttng_event" array. Caller must free(3).
 274  */
 275 extern int lttng_list_events(struct lttng_handle *handle,
 276                 const char *channel_name, struct lttng_event **events);
 277
 278 /*
 279  * List available tracepoints of a specific lttng domain.
 280  *
 281  * Return the size of the "lttng_event" array. Caller must free(3).
 282  */
 283 extern int lttng_list_tracepoints(struct lttng_handle *handle,
 284                 struct lttng_event **events);
 285
 286 /*
 287  * Check if a session daemon is alive.
 288  */
 289 extern int lttng_session_daemon_alive(void);
 290
 291 /*
 292  * Set tracing group for the *current* flow of execution.
 293  */
 294 extern int lttng_set_tracing_group(const char *name);
 295
 296 /*
 297  * Return a human readable error message of a lttng-tools error code.
 298  *
 299  * Parameter MUST be a negative value or else you'll get a generic message.
 300  */
 301 extern const char *lttng_strerror(int code);
 302
 303 /*
 304  * This call permits to register an "outside consumer" to a session and a lttng
 305  * domain. No consumer will be spawned and all fds/commands will go through the
 306  * socket path given (socket_path).
 307  *
 308  * NOTE: At the moment, if you use the liblttng-kconsumer, you can only use the
 309  * command socket. The error socket is not supported yet for roaming consumers.
 310  */
 311 extern int lttng_register_consumer(struct lttng_handle *handle,
 312                 const char *socket_path);
 313
 314 /*
 315  * Start tracing for *all* registered trace (kernel and user-space).
 316  */
 317 extern int lttng_start_tracing(struct lttng_handle *handle);
 318
 319 /*
 320  * Stop tracing for *all* registered trace (kernel and user-space).
 321  */
 322 extern int lttng_stop_tracing(struct lttng_handle *handle);
 323
 324 /*
 325  * Add context to event for a specific channel.
 326  *
 327  * If event_name is NULL, the context is applied to all event of the channel.
 328  * If channel_name is NULL, a lookup of the event's channel is done.
 329  * If both are NULL, the context is applied on all events of all channels.
 330  */
 331 extern int lttng_add_context(struct lttng_handle *handle,
 332                 struct lttng_event_context *ctx, const char *event_name,
 333                 const char *channel_name);
 334
 335 /*
 336  * Create or enable a kernel event.
 337  *
 338  * If the event you are trying to enable does not exist, it will be created,
 339  * else it is enabled.
 340  *
 341  * If channel_name is NULL, the default channel is used (channel0).
 342  */
 343 extern int lttng_enable_event(struct lttng_handle *handle,
 344                 struct lttng_event *ev, const char *channel_name);
 345
 346 /*
 347  * Create or enable a kernel channel.
 348  *
 349  * If name is NULL, the default channel is enabled (channel0).
 350  */
 351 extern int lttng_enable_channel(struct lttng_handle *handle,
 352                 struct lttng_channel *chan);
 353
 354 /*
 355  * Disable kernel event.
 356  *
 357  * If channel_name is NULL, the default channel is used (channel0).
 358  */
 359 extern int lttng_disable_event(struct lttng_handle *handle,
 360                 const char *name, const char *channel_name);
 361
 362 /*
 363  * Disable kernel channel.
 364  *
 365  * If channel_name is NULL, the default channel is disabled (channel0).
 366  */
 367 extern int lttng_disable_channel(struct lttng_handle *handle,
 368                 const char *name);
 369
 370 /*
 371  * Calibrate LTTng overhead.
 372  */
 373 extern int lttng_calibrate(struct lttng_handle *handle,
 374                 struct lttng_calibrate *calibrate);
 375
 376 /*
 377  * Set the default channel attributes for a specific domain and an allocated
 378  * lttng_channel_attr pointer.
 379  */
 380 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 381                 struct lttng_channel_attr *attr);
 382
 383 #endif /* _LTTNG_H */