| 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 | * LGPL-compatible code should include this header with : |
| 9 | * |
| 10 | * #define _LGPL_SOURCE |
| 11 | * #include <lttng.h> |
| 12 | * |
| 13 | * This library is free software; you can redistribute it and/or |
| 14 | * modify it under the terms of the GNU Lesser General Public |
| 15 | * License as published by the Free Software Foundation; only |
| 16 | * version 2.1 of the License. |
| 17 | * |
| 18 | * This library is distributed in the hope that it will be useful, |
| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 21 | * Lesser General Public License for more details. |
| 22 | * |
| 23 | * You should have received a copy of the GNU Lesser General Public |
| 24 | * License along with this library; if not, write to the Free Software |
| 25 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 26 | */ |
| 27 | |
| 28 | #ifndef _LTTNG_H |
| 29 | #define _LTTNG_H |
| 30 | |
| 31 | #include <asm/types.h> |
| 32 | #include <sys/types.h> |
| 33 | #include <stdint.h> |
| 34 | #include <limits.h> |
| 35 | |
| 36 | /* Default unix group name for tracing. */ |
| 37 | #define LTTNG_DEFAULT_TRACING_GROUP "tracing" |
| 38 | |
| 39 | /* Environment variable to set session daemon binary path. */ |
| 40 | #define LTTNG_SESSIOND_PATH_ENV "LTTNG_SESSIOND_PATH" |
| 41 | |
| 42 | /* Default trace output directory name */ |
| 43 | #define LTTNG_DEFAULT_TRACE_DIR_NAME "lttng-traces" |
| 44 | |
| 45 | /* |
| 46 | * Event symbol length. Copied from LTTng kernel ABI. |
| 47 | */ |
| 48 | #define LTTNG_SYMBOL_NAME_LEN 128 |
| 49 | |
| 50 | /* |
| 51 | * Every lttng_event_* structure both apply to kernel event and user-space |
| 52 | * event. |
| 53 | */ |
| 54 | |
| 55 | /* |
| 56 | * Domain type are the different possible tracers. |
| 57 | */ |
| 58 | enum lttng_domain_type { |
| 59 | LTTNG_DOMAIN_KERNEL, |
| 60 | LTTNG_DOMAIN_UST, |
| 61 | LTTNG_DOMAIN_UST_EXEC_NAME, |
| 62 | LTTNG_DOMAIN_UST_PID, |
| 63 | LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN, |
| 64 | }; |
| 65 | |
| 66 | struct lttng_domain { |
| 67 | enum lttng_domain_type type; |
| 68 | union { |
| 69 | pid_t pid; |
| 70 | char exec_name[NAME_MAX]; |
| 71 | } attr; |
| 72 | }; |
| 73 | |
| 74 | /* |
| 75 | * Instrumentation type of tracing event. |
| 76 | */ |
| 77 | enum lttng_event_type { |
| 78 | LTTNG_EVENT_TRACEPOINT, |
| 79 | LTTNG_EVENT_PROBE, |
| 80 | LTTNG_EVENT_FUNCTION, |
| 81 | }; |
| 82 | |
| 83 | /* |
| 84 | * LTTng consumer mode |
| 85 | */ |
| 86 | enum lttng_event_output { |
| 87 | LTTNG_EVENT_SPLICE = 0, |
| 88 | LTTNG_EVENT_MMAP = 1, |
| 89 | }; |
| 90 | |
| 91 | /* Event context possible type */ |
| 92 | enum lttng_event_context_type { |
| 93 | LTTNG_EVENT_CONTEXT_PID = 0, |
| 94 | LTTNG_EVENT_CONTEXT_PERF_COUNTER = 1, |
| 95 | LTTNG_EVENT_CONTEXT_COMM = 2, |
| 96 | LTTNG_EVENT_CONTEXT_PRIO = 3, |
| 97 | LTTNG_EVENT_CONTEXT_NICE = 4, |
| 98 | LTTNG_EVENT_CONTEXT_VPID = 5, |
| 99 | LTTNG_EVENT_CONTEXT_TID = 6, |
| 100 | LTTNG_EVENT_CONTEXT_VTID = 7, |
| 101 | LTTNG_EVENT_CONTEXT_PPID = 8, |
| 102 | LTTNG_EVENT_CONTEXT_VPPID = 9, |
| 103 | }; |
| 104 | |
| 105 | /* Perf counter attributes */ |
| 106 | struct lttng_event_perf_counter_ctx { |
| 107 | uint32_t type; |
| 108 | uint64_t config; |
| 109 | char name[LTTNG_SYMBOL_NAME_LEN]; |
| 110 | }; |
| 111 | |
| 112 | /* Event/Channel context */ |
| 113 | struct lttng_event_context { |
| 114 | enum lttng_event_context_type ctx; |
| 115 | union { |
| 116 | struct lttng_event_perf_counter_ctx perf_counter; |
| 117 | } u; |
| 118 | }; |
| 119 | |
| 120 | /* |
| 121 | * Event probe. |
| 122 | * |
| 123 | * Either addr is used or symbol_name and offset. |
| 124 | */ |
| 125 | struct lttng_event_probe_attr { |
| 126 | uint64_t addr; |
| 127 | |
| 128 | uint64_t offset; |
| 129 | char symbol_name[LTTNG_SYMBOL_NAME_LEN]; |
| 130 | }; |
| 131 | |
| 132 | /* |
| 133 | * Function tracer |
| 134 | */ |
| 135 | struct lttng_event_function_attr { |
| 136 | char symbol_name[LTTNG_SYMBOL_NAME_LEN]; |
| 137 | }; |
| 138 | |
| 139 | /* |
| 140 | * Generic lttng event |
| 141 | */ |
| 142 | struct lttng_event { |
| 143 | char name[LTTNG_SYMBOL_NAME_LEN]; |
| 144 | enum lttng_event_type type; |
| 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 | struct lttng_channel_attr attr; |
| 170 | }; |
| 171 | |
| 172 | /* |
| 173 | * Basic session information. |
| 174 | * |
| 175 | * This is an 'output data' meaning that it only comes *from* the session |
| 176 | * daemon *to* the lttng client. It's basically a 'human' representation of |
| 177 | * tracing entities (here a session). |
| 178 | */ |
| 179 | struct lttng_session { |
| 180 | char name[NAME_MAX]; |
| 181 | /* The path where traces are written */ |
| 182 | char path[PATH_MAX]; |
| 183 | }; |
| 184 | |
| 185 | /* |
| 186 | * Public LTTng control API |
| 187 | * |
| 188 | * For functions having a lttng domain type as parameter, if a bad value is |
| 189 | * given, NO default is applied and an error is returned. |
| 190 | * |
| 191 | * On success, all functions of the API return 0 or the size of the allocated |
| 192 | * array. |
| 193 | * |
| 194 | * On error, a negative value is returned being a specific lttng-tools error |
| 195 | * code which can be humanly interpreted with lttng_get_readable_code(err). |
| 196 | */ |
| 197 | |
| 198 | /* |
| 199 | * Session daemon control |
| 200 | */ |
| 201 | |
| 202 | /* |
| 203 | * Create tracing session using a name and a path where trace will be written. |
| 204 | */ |
| 205 | extern int lttng_create_session(const char *name, const char *path); |
| 206 | |
| 207 | /* |
| 208 | * Destroy tracing session. |
| 209 | * |
| 210 | * The session will not be useable anymore, tracing will stopped for all |
| 211 | * registered trace and tracing buffers will be flushed. |
| 212 | */ |
| 213 | extern int lttng_destroy_session(const char *name); |
| 214 | |
| 215 | /* |
| 216 | * List tracing sessions. |
| 217 | * |
| 218 | * Return the size of the "lttng_session" array. Caller must free(3) the |
| 219 | * returned data. |
| 220 | */ |
| 221 | extern int lttng_list_sessions(struct lttng_session **sessions); |
| 222 | |
| 223 | /* |
| 224 | * Check if a session daemon is alive. |
| 225 | */ |
| 226 | extern int lttng_session_daemon_alive(void); |
| 227 | |
| 228 | /* |
| 229 | * Set tracing group for the *current* flow of execution. |
| 230 | */ |
| 231 | extern int lttng_set_tracing_group(const char *name); |
| 232 | |
| 233 | /* |
| 234 | * Set the session name of the *current* flow of execution. |
| 235 | * |
| 236 | * This is a VERY important things to do before doing any tracing actions. If |
| 237 | * it's not done, you'll get an error saying that the session is not found. |
| 238 | * It avoids the use of a session name on every API call. |
| 239 | */ |
| 240 | extern void lttng_set_session_name(const char *name); |
| 241 | |
| 242 | /* |
| 243 | * Return a human readable error message of a lttng-tools error code. |
| 244 | * |
| 245 | * Parameter MUST be a negative value or else you'll get a generic message. |
| 246 | */ |
| 247 | extern const char *lttng_get_readable_code(int code); |
| 248 | |
| 249 | /* |
| 250 | * Start tracing for *all* registered trace (kernel and user-space). |
| 251 | */ |
| 252 | extern int lttng_start_tracing(const char *session_name); |
| 253 | |
| 254 | /* |
| 255 | * Stop tracing for *all* registered trace (kernel and user-space). |
| 256 | */ |
| 257 | extern int lttng_stop_tracing(const char *session_name); |
| 258 | |
| 259 | /* |
| 260 | * Add context to event for a specific channel. |
| 261 | * |
| 262 | * If event_name is NULL, the context is applied to all event of the channel. |
| 263 | * If channel_name is NULL, a lookup of the event's channel is done. |
| 264 | * If both are NULL, the context is applied on all events of all channels. |
| 265 | */ |
| 266 | |
| 267 | extern int lttng_add_context(struct lttng_domain *domain, |
| 268 | struct lttng_event_context *ctx, const char *event_name, |
| 269 | const char *channel_name); |
| 270 | |
| 271 | /* |
| 272 | * Create or enable a kernel event. |
| 273 | * |
| 274 | * If the event you are trying to enable does not exist, it will be created, |
| 275 | * else it is enabled. |
| 276 | * |
| 277 | * If channel_name is NULL, the default channel is used (channel0). |
| 278 | */ |
| 279 | extern int lttng_enable_event(struct lttng_domain *domain, struct lttng_event *ev, |
| 280 | const char *channel_name); |
| 281 | |
| 282 | /* |
| 283 | * Create or enable a kernel channel. |
| 284 | * |
| 285 | * If name is NULL, the default channel is enabled (channel0). |
| 286 | */ |
| 287 | extern int lttng_enable_channel(struct lttng_domain *domain, |
| 288 | struct lttng_channel *chan); |
| 289 | |
| 290 | /* |
| 291 | * Disable kernel event. |
| 292 | * |
| 293 | * If channel_name is NULL, the default channel is used (channel0). |
| 294 | */ |
| 295 | extern int lttng_disable_event(struct lttng_domain *domain, const char *name, |
| 296 | const char *channel_name); |
| 297 | |
| 298 | /* |
| 299 | * Disable kernel channel. |
| 300 | * |
| 301 | * If channel_name is NULL, the default channel is disabled (channel0). |
| 302 | */ |
| 303 | extern int lttng_disable_channel(struct lttng_domain *domain, |
| 304 | const char *name); |
| 305 | |
| 306 | /* |
| 307 | * List kernel events. |
| 308 | * |
| 309 | * Return the size of the allocated event list. Caller must free(3) the data. |
| 310 | */ |
| 311 | extern int lttng_list_events(struct lttng_domain *domain, char **event_list); |
| 312 | |
| 313 | #endif /* _LTTNG_H */ |