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 program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program 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
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, 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 struct lttng_domain {
  62         enum lttng_domain_type type;
  63         union {
  64                 pid_t pid;
  65                 char exec_name[NAME_MAX];
  66         } attr;
  67 };
  68
  69 /*
  70  * Instrumentation type of tracing event.
  71  */
  72 enum lttng_event_type {
  73         LTTNG_EVENT_TRACEPOINT,
  74         LTTNG_EVENT_PROBE,
  75         LTTNG_EVENT_FUNCTION,
  76 };
  77
  78 /*
  79  * LTTng consumer mode
  80  */
  81 enum lttng_event_output {
  82         LTTNG_EVENT_SPLICE = 0,
  83         LTTNG_EVENT_MMAP   = 1,
  84 };
  85
  86 /* Event context possible type */
  87 enum lttng_event_context_type {
  88         LTTNG_EVENT_CONTEXT_PID                = 0,
  89         LTTNG_EVENT_CONTEXT_PERF_COUNTER       = 1,
  90         LTTNG_EVENT_CONTEXT_COMM               = 2,
  91         LTTNG_EVENT_CONTEXT_PRIO               = 3,
  92         LTTNG_EVENT_CONTEXT_NICE               = 4,
  93         LTTNG_EVENT_CONTEXT_VPID               = 5,
  94         LTTNG_EVENT_CONTEXT_TID                = 6,
  95         LTTNG_EVENT_CONTEXT_VTID               = 7,
  96         LTTNG_EVENT_CONTEXT_PPID               = 8,
  97         LTTNG_EVENT_CONTEXT_VPPID              = 9,
  98 };
  99
 100 /* Perf counter attributes */
 101 struct lttng_event_perf_counter_ctx {
 102         uint32_t type;
 103         uint64_t config;
 104         char name[LTTNG_SYMBOL_NAME_LEN];
 105 };
 106
 107 /* Event/Channel context */
 108 struct lttng_event_context {
 109         enum lttng_event_context_type ctx;
 110         union {
 111                 struct lttng_event_perf_counter_ctx perf_counter;
 112         } u;
 113 };
 114
 115 /*
 116  * Event probe.
 117  *
 118  * Either addr is used or symbol_name and offset.
 119  */
 120 struct lttng_event_probe_attr {
 121         uint64_t addr;
 122
 123         uint64_t offset;
 124         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 125 };
 126
 127 /*
 128  * Function tracer
 129  */
 130 struct lttng_event_function_attr {
 131         char symbol_name[LTTNG_SYMBOL_NAME_LEN];
 132 };
 133
 134 /*
 135  * Generic lttng event
 136  */
 137 struct lttng_event {
 138         char name[LTTNG_SYMBOL_NAME_LEN];
 139         enum lttng_event_type type;
 140         /* Per event type configuration */
 141         union {
 142                 struct lttng_event_probe_attr probe;
 143                 struct lttng_event_function_attr ftrace;
 144         } attr;
 145 };
 146
 147 /*
 148  * Tracer channel attributes. For both kernel and user-space.
 149  */
 150 struct lttng_channel_attr {
 151         int overwrite;                      /* 1: overwrite, 0: discard */
 152         uint64_t subbuf_size;               /* bytes */
 153         uint64_t num_subbuf;                /* power of 2 */
 154         unsigned int switch_timer_interval; /* usec */
 155         unsigned int read_timer_interval;   /* usec */
 156         enum lttng_event_output output;     /* splice, mmap */
 157 };
 158
 159 /*
 160  * Channel information structure. For both kernel and user-space.
 161  */
 162 struct lttng_channel {
 163         char name[NAME_MAX];
 164         struct lttng_channel_attr attr;
 165 };
 166
 167 /*
 168  * Basic session information.
 169  *
 170  * This is an 'output data' meaning that it only comes *from* the session
 171  * daemon *to* the lttng client. It's basically a 'human' representation of
 172  * tracing entities (here a session).
 173  */
 174 struct lttng_session {
 175         char name[NAME_MAX];
 176         /* The path where traces are written */
 177         char path[PATH_MAX];
 178 };
 179
 180 /*
 181  * Public LTTng control API
 182  *
 183  * For functions having a lttng domain type as parameter, if a bad value is
 184  * given, NO default is applied and an error is returned.
 185  *
 186  * On success, all functions of the API return 0 or the size of the allocated
 187  * array.
 188  *
 189  * On error, a negative value is returned being a specific lttng-tools error
 190  * code which can be humanly interpreted with lttng_get_readable_code(err).
 191  */
 192
 193 /*
 194  * Session daemon control
 195  */
 196
 197 /*
 198  * Create tracing session using a name and a path where trace will be written.
 199  */
 200 extern int lttng_create_session(char *name, char *path);
 201
 202 /*
 203  * Destroy tracing session.
 204  *
 205  * The session will not be useable anymore, tracing will stopped for all
 206  * registered trace and tracing buffers will be flushed.
 207  */
 208 extern int lttng_destroy_session(char *name);
 209
 210 /*
 211  * List tracing sessions.
 212  *
 213  * Return the size of the "lttng_session" array. Caller must free(3) the
 214  * returned data.
 215  */
 216 extern int lttng_list_sessions(struct lttng_session **sessions);
 217
 218 /*
 219  * Check if a session daemon is alive.
 220  */
 221 extern int lttng_session_daemon_alive(void);
 222
 223 /*
 224  * Set tracing group for the *current* flow of execution.
 225  */
 226 extern int lttng_set_tracing_group(const char *name);
 227
 228 /*
 229  * Set the session name of the *current* flow of execution.
 230  *
 231  * This is a VERY important things to do before doing any tracing actions. If
 232  * it's not done, you'll get an error saying that the session is not found.
 233  * It avoids the use of a session name on every API call.
 234  */
 235 extern void lttng_set_session_name(char *name);
 236
 237 /*
 238  * Return a human readable error message of a lttng-tools error code.
 239  *
 240  * Parameter MUST be a negative value or else you'll get a generic message.
 241  */
 242 extern const char *lttng_get_readable_code(int code);
 243
 244 /*
 245  * Start tracing for *all* registered trace (kernel and user-space).
 246  */
 247 extern int lttng_start_tracing(char *session_name);
 248
 249 /*
 250  * Stop tracing for *all* registered trace (kernel and user-space).
 251  */
 252 extern int lttng_stop_tracing(char *session_name);
 253
 254 /*
 255  * Add context to event for a specific channel.
 256  *
 257  * If event_name is NULL, the context is applied to all event of the channel.
 258  * If channel_name is NULL, a lookup of the event's channel is done.
 259  * If both are NULL, the context is applied on all events of all channels.
 260  */
 261
 262 extern int lttng_add_context(struct lttng_domain *domain,
 263                 struct lttng_event_context *ctx, char *event_name, char *channel_name);
 264
 265 /*
 266  * Create or enable a kernel event.
 267  *
 268  * If the event you are trying to enable does not exist, it will be created,
 269  * else it is enabled.
 270  *
 271  * If channel_name is NULL, the default channel is used (channel0).
 272  */
 273 extern int lttng_enable_event(struct lttng_domain *domain, struct lttng_event *ev,
 274                 char *channel_name);
 275
 276 /*
 277  * Create or enable a kernel channel.
 278  *
 279  * If name is NULL, the default channel is enabled (channel0).
 280  */
 281 extern int lttng_enable_channel(struct lttng_domain *domain, struct lttng_channel *chan);
 282
 283 /*
 284  * Disable kernel event.
 285  *
 286  * If channel_name is NULL, the default channel is used (channel0).
 287  */
 288 extern int lttng_disable_event(struct lttng_domain *domain, char *name,
 289                 char *channel_name);
 290
 291 /*
 292  * Disable kernel channel.
 293  *
 294  * If channel_name is NULL, the default channel is disabled (channel0).
 295  */
 296 extern int lttng_disable_channel(struct lttng_domain *domain, char *name);
 297
 298 /*
 299  * List kernel events.
 300  *
 301  * Return the size of the allocated event list. Caller must free(3) the data.
 302  */
 303 extern int lttng_list_events(struct lttng_domain *domain, char **event_list);
 304
 305 #endif /* _LTTNG_H */