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 <asm/types.h>
  27 #include <sys/types.h>
  28 #include <stdint.h>
  29 #include <limits.h>
  30
  31 /* Default unix group name for tracing. */
  32 #define LTTNG_DEFAULT_TRACING_GROUP "tracing"
  33
  34 /* Environment variable to set session daemon binary path. */
  35 #define LTTNG_SESSIOND_PATH_ENV "LTTNG_SESSIOND_PATH"
  36
  37 /* Default trace output directory name */
  38 #define LTTNG_DEFAULT_TRACE_DIR_NAME "lttng-traces"
  39
  40 /*
  41  * Event symbol length. Copied from LTTng kernel ABI.
  42  */
  43 #define LTTNG_SYMBOL_NAME_LEN 128
  44
  45 /*
  46  * Every lttng_event_* structure both apply to kernel event and user-space
  47  * event.
  48  */
  49
  50 /*
  51  * Domain type are the different possible tracers.
  52  */
  53 enum lttng_domain_type {
  54         LTTNG_DOMAIN_KERNEL,
  55         LTTNG_DOMAIN_UST,
  56         LTTNG_DOMAIN_UST_EXEC_NAME,
  57         LTTNG_DOMAIN_UST_PID,
  58         LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN,
  59 };
  60
  61 /*
  62  * Instrumentation type of tracing event.
  63  */
  64 enum lttng_event_type {
  65         LTTNG_EVENT_TRACEPOINT,
  66         LTTNG_EVENT_PROBE,
  67         LTTNG_EVENT_FUNCTION,
  68         LTTNG_EVENT_FUNCTION_ENTRY,
  69 };
  70
  71 /*
  72  * LTTng consumer mode
  73  */
  74 enum lttng_event_output {
  75         LTTNG_EVENT_SPLICE = 0,
  76         LTTNG_EVENT_MMAP   = 1,
  77 };
  78
  79 /* Event context possible type */
  80 enum lttng_event_context_type {
  81         LTTNG_EVENT_CONTEXT_PID                = 0,
  82         LTTNG_EVENT_CONTEXT_PERF_COUNTER       = 1,
  83         LTTNG_EVENT_CONTEXT_COMM               = 2,
  84         LTTNG_EVENT_CONTEXT_PRIO               = 3,
  85         LTTNG_EVENT_CONTEXT_NICE               = 4,
  86         LTTNG_EVENT_CONTEXT_VPID               = 5,
  87         LTTNG_EVENT_CONTEXT_TID                = 6,
  88         LTTNG_EVENT_CONTEXT_VTID               = 7,
  89         LTTNG_EVENT_CONTEXT_PPID               = 8,
  90         LTTNG_EVENT_CONTEXT_VPPID              = 9,
  91 };
  92
  93 struct lttng_domain {
  94         enum lttng_domain_type type;
  95         union {
  96                 pid_t pid;
  97                 char exec_name[NAME_MAX];
  98         } attr;
  99 };
 100
 101 /* Perf counter attributes */
 102 struct lttng_event_perf_counter_ctx {
 103         uint32_t type;
 104         uint64_t config;
 105         char name[LTTNG_SYMBOL_NAME_LEN];
 106 };
 107
 108 /* Event/Channel context */
 109 struct lttng_event_context {
 110         enum lttng_event_context_type ctx;
 111         union {
 112                 struct lttng_event_perf_counter_ctx perf_counter;
 113         } u;
 114 };
 115
 116 /*
 117  * Event probe.
 118  *
 119  * Either addr is used or symbol_name and offset.
 120  */
 121 struct lttng_event_probe_attr {
 122         uint64_t addr;
 123
 124         uint64_t offset;
 125         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 126 };
 127
 128 /*
 129  * Function tracer
 130  */
 131 struct lttng_event_function_attr {
 132         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 133 };
 134
 135 /*
 136  * Generic lttng event
 137  */
 138 struct lttng_event {
 139         char name[LTTNG_SYMBOL_NAME_LEN];
 140         enum lttng_event_type type;
 141         uint32_t enabled;
 142         /* Per event type configuration */
 143         union {
 144                 struct lttng_event_probe_attr probe;
 145                 struct lttng_event_function_attr ftrace;
 146         } attr;
 147 };
 148
 149 /*
 150  * Tracer channel attributes. For both kernel and user-space.
 151  */
 152 struct lttng_channel_attr {
 153         int overwrite;                      /* 1: overwrite, 0: discard */
 154         uint64_t subbuf_size;               /* bytes */
 155         uint64_t num_subbuf;                /* power of 2 */
 156         unsigned int switch_timer_interval; /* usec */
 157         unsigned int read_timer_interval;   /* usec */
 158         enum lttng_event_output output;     /* splice, mmap */
 159 };
 160
 161 /*
 162  * Channel information structure. For both kernel and user-space.
 163  */
 164 struct lttng_channel {
 165         char name[NAME_MAX];
 166         uint32_t enabled;
 167         struct lttng_channel_attr attr;
 168 };
 169
 170 /*
 171  * Basic session information.
 172  *
 173  * This is an 'output data' meaning that it only comes *from* the session
 174  * daemon *to* the lttng client. It's basically a 'human' representation of
 175  * tracing entities (here a session).
 176  */
 177 struct lttng_session {
 178         char name[NAME_MAX];
 179         /* The path where traces are written */
 180         char path[PATH_MAX];
 181 };
 182
 183 /*
 184  * Public LTTng control API
 185  *
 186  * For functions having a lttng domain type as parameter, if a bad value is
 187  * given, NO default is applied and an error is returned.
 188  *
 189  * On success, all functions of the API return 0 or the size of the allocated
 190  * array.
 191  *
 192  * On error, a negative value is returned being a specific lttng-tools error
 193  * code which can be humanly interpreted with lttng_get_readable_code(err).
 194  */
 195
 196 /*
 197  * Session daemon control
 198  */
 199
 200 /*
 201  * Create tracing session using a name and a path where trace will be written.
 202  */
 203 extern int lttng_create_session(const char *name, const char *path);
 204
 205 /*
 206  * Destroy tracing session.
 207  *
 208  * The session will not be useable anymore, tracing will stopped for all
 209  * registered trace and tracing buffers will be flushed.
 210  */
 211 extern int lttng_destroy_session(const char *name);
 212
 213 /*
 214  * List all tracing sessions.
 215  *
 216  * Return the size of the "lttng_session" array. Caller must free(3).
 217  */
 218 extern int lttng_list_sessions(struct lttng_session **sessions);
 219
 220 /*
 221  * List registered domain(s) of the session.
 222  *
 223  * Return the size of the "lttng_domain" array. Caller must free(3).
 224  */
 225 extern int lttng_list_domains(const char *session_name,
 226                 struct lttng_domain **domains);
 227
 228 /*
 229  * List channel(s) of a session.
 230  *
 231  * Return the size of the "lttng_channel" array. Caller must free(3).
 232  */
 233 extern int lttng_list_channels(struct lttng_domain *domain,
 234                 const char *session_name, struct lttng_channel **channels);
 235
 236 /*
 237  * List event(s) of a session channel.
 238  *
 239  * Return the size of the "lttng_event" array. Caller must free(3).
 240  */
 241 extern int lttng_list_events(struct lttng_domain *domain,
 242                 const char *session_name, const char *channel_name,
 243                 struct lttng_event **events);
 244
 245 /*
 246  * List available kernel tracing events
 247  *
 248  * Return the size of the "lttng_event" array. Caller must free(3).
 249  */
 250 extern int lttng_list_kernel_events(struct lttng_event **events);
 251
 252 /*
 253  * Check if a session daemon is alive.
 254  */
 255 extern int lttng_session_daemon_alive(void);
 256
 257 /*
 258  * Set tracing group for the *current* flow of execution.
 259  */
 260 extern int lttng_set_tracing_group(const char *name);
 261
 262 /*
 263  * Set the session name of the *current* flow of execution.
 264  *
 265  * This is a VERY important things to do before doing any tracing actions. If
 266  * it's not done, you'll get an error saying that the session is not found.
 267  * It avoids the use of a session name on every API call.
 268  */
 269 extern void lttng_set_session_name(const char *name);
 270
 271 /*
 272  * Return a human readable error message of a lttng-tools error code.
 273  *
 274  * Parameter MUST be a negative value or else you'll get a generic message.
 275  */
 276 extern const char *lttng_get_readable_code(int code);
 277
 278 /*
 279  * Start tracing for *all* registered trace (kernel and user-space).
 280  */
 281 extern int lttng_start_tracing(const char *session_name);
 282
 283 /*
 284  * Stop tracing for *all* registered trace (kernel and user-space).
 285  */
 286 extern int lttng_stop_tracing(const char *session_name);
 287
 288 /*
 289  * Add context to event for a specific channel.
 290  *
 291  * If event_name is NULL, the context is applied to all event of the channel.
 292  * If channel_name is NULL, a lookup of the event's channel is done.
 293  * If both are NULL, the context is applied on all events of all channels.
 294  */
 295
 296 extern int lttng_add_context(struct lttng_domain *domain,
 297                 struct lttng_event_context *ctx, const char *event_name,
 298                 const char *channel_name);
 299
 300 /*
 301  * Create or enable a kernel event.
 302  *
 303  * If the event you are trying to enable does not exist, it will be created,
 304  * else it is enabled.
 305  *
 306  * If channel_name is NULL, the default channel is used (channel0).
 307  */
 308 extern int lttng_enable_event(struct lttng_domain *domain, struct lttng_event *ev,
 309                 const char *channel_name);
 310
 311 /*
 312  * Create or enable a kernel channel.
 313  *
 314  * If name is NULL, the default channel is enabled (channel0).
 315  */
 316 extern int lttng_enable_channel(struct lttng_domain *domain,
 317                 struct lttng_channel *chan);
 318
 319 /*
 320  * Disable kernel event.
 321  *
 322  * If channel_name is NULL, the default channel is used (channel0).
 323  */
 324 extern int lttng_disable_event(struct lttng_domain *domain, const char *name,
 325                 const char *channel_name);
 326
 327 /*
 328  * Disable kernel channel.
 329  *
 330  * If channel_name is NULL, the default channel is disabled (channel0).
 331  */
 332 extern int lttng_disable_channel(struct lttng_domain *domain,
 333                 const char *name);
 334
 335 /*
 336  * List kernel events.
 337  *
 338  * Return the size of the allocated event list. Caller must free(3) the data.
 339  */
 340 //extern int lttng_list_events(struct lttng_domain *domain, char **event_list);
 341
 342 #endif /* _LTTNG_H */