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