include/lttng/tracepoint.h

   1 #ifndef _LTTNG_TRACEPOINT_H
   2 #define _LTTNG_TRACEPOINT_H
   3
   4 /*
   5  * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  */
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <lttng/tracepoint-types.h>
  29 #include <lttng/tracepoint-rcu.h>
  30 #include <urcu/compiler.h>
  31 #include <dlfcn.h>      /* for dlopen */
  32 #include <string.h>     /* for memset */
  33 #include <lttng/ust-config.h>   /* for sdt */
  34 #include <lttng/ust-compiler.h>
  35
  36 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  37 #define SDT_USE_VARIADIC
  38 #include <sys/sdt.h>
  39 #else
  40 #define STAP_PROBEV(...)
  41 #endif
  42
  43 #ifdef __cplusplus
  44 extern "C" {
  45 #endif
  46
  47 #define tracepoint(provider, name, ...)                                     \
  48         do {                                                                \
  49                 STAP_PROBEV(provider, name, ## __VA_ARGS__);                \
  50                 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
  51                         __tracepoint_cb_##provider##___##name(__VA_ARGS__); \
  52         } while (0)
  53
  54 #define TP_ARGS(...)       __VA_ARGS__
  55
  56 /*
  57  * TP_ARGS takes tuples of type, argument separated by a comma.
  58  * It can take up to 10 tuples (which means that less than 10 tuples is
  59  * fine too).
  60  * Each tuple is also separated by a comma.
  61  */
  62 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  63                 _tokena##_tokenb
  64 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  65                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  66 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  67                 _tokena##_tokenb##_tokenc
  68 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  69                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  70 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  71                 _tokena##_tokenb##_tokenc##_tokend
  72 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  73                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  74
  75 /*
  76  * _TP_EXVAR* extract the var names.
  77  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  78  */
  79 #define _TP_EXVAR0()
  80 #define _TP_EXVAR1(a)
  81 #define _TP_EXVAR2(a,b)                                         b
  82 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  83 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  84 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  85 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  86 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  87 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  88 #define _TP_EXVAR16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p)            b,d,f,h,j,l,n,p
  89 #define _TP_EXVAR18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r)        b,d,f,h,j,l,n,p,r
  90 #define _TP_EXVAR20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t)    b,d,f,h,j,l,n,p,r,t
  91
  92 #define _TP_EXDATA_VAR0()                                               __tp_data
  93 #define _TP_EXDATA_VAR1(a)                                              __tp_data
  94 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
  95 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
  96 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
  97 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
  98 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
  99 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 100 #define _TP_EXDATA_VAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                   __tp_data,b,d,f,h,j,l,n
 101 #define _TP_EXDATA_VAR16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p)               __tp_data,b,d,f,h,j,l,n,p
 102 #define _TP_EXDATA_VAR18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r)           __tp_data,b,d,f,h,j,l,n,p,r
 103 #define _TP_EXDATA_VAR20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t)       __tp_data,b,d,f,h,j,l,n,p,r,t
 104
 105 /*
 106  * _TP_EXPROTO* extract tuples of type, var.
 107  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 108  */
 109 #define _TP_EXPROTO0()                                          void
 110 #define _TP_EXPROTO1(a)                                         void
 111 #define _TP_EXPROTO2(a,b)                                       a b
 112 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 113 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 114 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 115 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 116 #define _TP_EXPROTO12(a,b,c,d,e,f,g,h,i,j,k,l)                  a b,c d,e f,g h,i j,k l
 117 #define _TP_EXPROTO14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)              a b,c d,e f,g h,i j,k l,m n
 118 #define _TP_EXPROTO16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p)          a b,c d,e f,g h,i j,k l,m n,o p
 119 #define _TP_EXPROTO18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r)      a b,c d,e f,g h,i j,k l,m n,o p,q r
 120 #define _TP_EXPROTO20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t)  a b,c d,e f,g h,i j,k l,m n,o p,q r,s t
 121
 122 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 123 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 124 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 125 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 126 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 127 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 128 #define _TP_EXDATA_PROTO10(a,b,c,d,e,f,g,h,i,j)                         void *__tp_data,a b,c d,e f,g h,i j
 129 #define _TP_EXDATA_PROTO12(a,b,c,d,e,f,g,h,i,j,k,l)                     void *__tp_data,a b,c d,e f,g h,i j,k l
 130 #define _TP_EXDATA_PROTO14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                 void *__tp_data,a b,c d,e f,g h,i j,k l,m n
 131 #define _TP_EXDATA_PROTO16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p)             void *__tp_data,a b,c d,e f,g h,i j,k l,m n,o p
 132 #define _TP_EXDATA_PROTO18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r)         void *__tp_data,a b,c d,e f,g h,i j,k l,m n,o p,q r
 133 #define _TP_EXDATA_PROTO20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t)     void *__tp_data,a b,c d,e f,g h,i j,k l,m n,o p,q r,s t
 134
 135 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 136 #define _TP_NARGS(...)                  __TP_NARGS(__VA_ARGS__, 20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0)
 137 #define __TP_NARGS(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12,_13,_14,_15,_16,_17,_18,_19,_20, N, ...)   N
 138 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 139 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 140 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 141 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 142 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 143 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 144 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 145 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 146 #define _TP_PARAMS(...)                 __VA_ARGS__
 147
 148 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 149 extern struct tracepoint __tracepoint_##_provider##___##_name;                          \
 150 static inline lttng_ust_notrace                                                         \
 151 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__));              \
 152 static inline                                                                           \
 153 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 154 {                                                                                       \
 155         struct tracepoint_probe *__tp_probe;                                            \
 156                                                                                         \
 157         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 158                 return;                                                                 \
 159         tp_rcu_read_lock_bp();                                                          \
 160         __tp_probe = tp_rcu_dereference_bp(__tracepoint_##_provider##___##_name.probes); \
 161         if (caa_unlikely(!__tp_probe))                                                  \
 162                 goto end;                                                               \
 163         do {                                                                            \
 164                 void (*__tp_cb)(void) = __tp_probe->func;                                       \
 165                 void *__tp_data = __tp_probe->data;                                     \
 166                                                                                         \
 167                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 168                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 169         } while ((++__tp_probe)->func);                                                 \
 170 end:                                                                                    \
 171         tp_rcu_read_unlock_bp();                                                        \
 172 }                                                                                       \
 173 static inline lttng_ust_notrace                                                         \
 174 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 175                 void (*func)(void), void *data);                                        \
 176 static inline                                                                           \
 177 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 178                 void (*func)(void), void *data)                                         \
 179 {                                                                                       \
 180         __tracepoint_probe_register(name, func, data,                                   \
 181                 __tracepoint_##_provider##___##_name.signature);                        \
 182 }                                                                                       \
 183 static inline lttng_ust_notrace                                                         \
 184 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 185                 void (*func)(void), void *data);                                        \
 186 static inline                                                                           \
 187 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 188                 void (*func)(void), void *data)                                         \
 189 {                                                                                       \
 190         __tracepoint_probe_unregister(name, func, data);                                \
 191 }
 192
 193 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 194                 void *data, const char *signature);
 195 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 196                 void *data);
 197
 198 /*
 199  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 200  * shared across objects in a module/main executable.
 201  */
 202 struct tracepoint_dlopen {
 203         void *liblttngust_handle;
 204
 205         int (*tracepoint_register_lib)(struct tracepoint * const *tracepoints_start,
 206                 int tracepoints_count);
 207         int (*tracepoint_unregister_lib)(struct tracepoint * const *tracepoints_start);
 208 #ifndef _LGPL_SOURCE
 209         void (*rcu_read_lock_sym_bp)(void);
 210         void (*rcu_read_unlock_sym_bp)(void);
 211         void *(*rcu_dereference_sym_bp)(void *p);
 212 #endif
 213 };
 214
 215 extern struct tracepoint_dlopen tracepoint_dlopen;
 216
 217 #if defined(TRACEPOINT_DEFINE) || defined(TRACEPOINT_CREATE_PROBES)
 218
 219 /*
 220  * These weak symbols, the constructor, and destructor take care of
 221  * registering only _one_ instance of the tracepoints per shared-ojbect
 222  * (or for the whole main program).
 223  */
 224 int __tracepoint_registered
 225         __attribute__((weak, visibility("hidden")));
 226 int __tracepoint_ptrs_registered
 227         __attribute__((weak, visibility("hidden")));
 228 struct tracepoint_dlopen tracepoint_dlopen
 229         __attribute__((weak, visibility("hidden")));
 230
 231 #ifndef _LGPL_SOURCE
 232 static inline void lttng_ust_notrace
 233 __tracepoint__init_urcu_sym(void);
 234 static inline void
 235 __tracepoint__init_urcu_sym(void)
 236 {
 237         /*
 238          * Symbols below are needed by tracepoint call sites and probe
 239          * providers.
 240          */
 241         if (!tracepoint_dlopen.rcu_read_lock_sym_bp)
 242                 tracepoint_dlopen.rcu_read_lock_sym_bp =
 243                         URCU_FORCE_CAST(void (*)(void),
 244                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 245                                         "tp_rcu_read_lock_bp"));
 246         if (!tracepoint_dlopen.rcu_read_unlock_sym_bp)
 247                 tracepoint_dlopen.rcu_read_unlock_sym_bp =
 248                         URCU_FORCE_CAST(void (*)(void),
 249                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 250                                         "tp_rcu_read_unlock_bp"));
 251         if (!tracepoint_dlopen.rcu_dereference_sym_bp)
 252                 tracepoint_dlopen.rcu_dereference_sym_bp =
 253                         URCU_FORCE_CAST(void *(*)(void *p),
 254                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 255                                         "tp_rcu_dereference_sym_bp"));
 256 }
 257 #else
 258 static inline void lttng_ust_notrace
 259 __tracepoint__init_urcu_sym(void);
 260 static inline void
 261 __tracepoint__init_urcu_sym(void)
 262 {
 263 }
 264 #endif
 265
 266 static void lttng_ust_notrace __attribute__((constructor))
 267 __tracepoints__init(void);
 268 static void
 269 __tracepoints__init(void)
 270 {
 271         if (__tracepoint_registered++)
 272                 return;
 273
 274         if (!tracepoint_dlopen.liblttngust_handle)
 275                 tracepoint_dlopen.liblttngust_handle =
 276                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 277         if (!tracepoint_dlopen.liblttngust_handle)
 278                 return;
 279         __tracepoint__init_urcu_sym();
 280 }
 281
 282 static void lttng_ust_notrace __attribute__((destructor))
 283 __tracepoints__destroy(void);
 284 static void
 285 __tracepoints__destroy(void)
 286 {
 287         int ret;
 288
 289         if (--__tracepoint_registered)
 290                 return;
 291         if (tracepoint_dlopen.liblttngust_handle && !__tracepoint_ptrs_registered) {
 292                 ret = dlclose(tracepoint_dlopen.liblttngust_handle);
 293                 if (ret) {
 294                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 295                         abort();
 296                 }
 297                 memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
 298         }
 299 }
 300
 301 #endif
 302
 303 #ifdef TRACEPOINT_DEFINE
 304
 305 /*
 306  * These weak symbols, the constructor, and destructor take care of
 307  * registering only _one_ instance of the tracepoints per shared-ojbect
 308  * (or for the whole main program).
 309  */
 310 extern struct tracepoint * const __start___tracepoints_ptrs[]
 311         __attribute__((weak, visibility("hidden")));
 312 extern struct tracepoint * const __stop___tracepoints_ptrs[]
 313         __attribute__((weak, visibility("hidden")));
 314
 315 /*
 316  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 317  * unresolved symbol that requires the provider to be linked in. When
 318  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 319  * unresolved symbol that depends on having the provider linked in,
 320  * otherwise the linker complains. This deals with use of static
 321  * libraries, ensuring that the linker does not remove the provider
 322  * object from the executable.
 323  */
 324 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 325 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 326 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 327 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 328 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 329
 330 /*
 331  * Note: to allow PIC code, we need to allow the linker to update the pointers
 332  * in the __tracepoints_ptrs section.
 333  * Therefore, this section is _not_ const (read-only).
 334  */
 335 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 336
 337 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 338         extern int __tracepoint_provider_##_provider;                           \
 339         static const char __tp_strtab_##_provider##___##_name[]                 \
 340                 __attribute__((section("__tracepoints_strings"))) =             \
 341                         #_provider ":" #_name;                                  \
 342         struct tracepoint __tracepoint_##_provider##___##_name                  \
 343                 __attribute__((section("__tracepoints"))) =                     \
 344                 {                                                               \
 345                         __tp_strtab_##_provider##___##_name,                    \
 346                         0,                                                      \
 347                         NULL,                                                   \
 348                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 349                         _TP_EXTRACT_STRING(_args),                              \
 350                 };                                                              \
 351         static struct tracepoint * __tracepoint_ptr_##_provider##___##_name     \
 352                 __attribute__((used, section("__tracepoints_ptrs"))) =          \
 353                         &__tracepoint_##_provider##___##_name;
 354
 355 static void lttng_ust_notrace __attribute__((constructor))
 356 __tracepoints__ptrs_init(void);
 357 static void
 358 __tracepoints__ptrs_init(void)
 359 {
 360         if (__tracepoint_ptrs_registered++)
 361                 return;
 362         if (!tracepoint_dlopen.liblttngust_handle)
 363                 tracepoint_dlopen.liblttngust_handle =
 364                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 365         if (!tracepoint_dlopen.liblttngust_handle)
 366                 return;
 367         tracepoint_dlopen.tracepoint_register_lib =
 368                 URCU_FORCE_CAST(int (*)(struct tracepoint * const *, int),
 369                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 370                                         "tracepoint_register_lib"));
 371         tracepoint_dlopen.tracepoint_unregister_lib =
 372                 URCU_FORCE_CAST(int (*)(struct tracepoint * const *),
 373                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 374                                         "tracepoint_unregister_lib"));
 375         __tracepoint__init_urcu_sym();
 376         if (tracepoint_dlopen.tracepoint_register_lib) {
 377                 tracepoint_dlopen.tracepoint_register_lib(__start___tracepoints_ptrs,
 378                                 __stop___tracepoints_ptrs -
 379                                 __start___tracepoints_ptrs);
 380         }
 381 }
 382
 383 static void lttng_ust_notrace __attribute__((destructor))
 384 __tracepoints__ptrs_destroy(void);
 385 static void
 386 __tracepoints__ptrs_destroy(void)
 387 {
 388         int ret;
 389
 390         if (--__tracepoint_ptrs_registered)
 391                 return;
 392         if (tracepoint_dlopen.tracepoint_unregister_lib)
 393                 tracepoint_dlopen.tracepoint_unregister_lib(__start___tracepoints_ptrs);
 394         if (tracepoint_dlopen.liblttngust_handle && !__tracepoint_registered) {
 395                 ret = dlclose(tracepoint_dlopen.liblttngust_handle);
 396                 if (ret) {
 397                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 398                         abort();
 399                 }
 400                 memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
 401         }
 402 }
 403
 404 #else /* TRACEPOINT_DEFINE */
 405
 406 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 407
 408 #endif /* #else TRACEPOINT_DEFINE */
 409
 410 #ifdef __cplusplus
 411 }
 412 #endif
 413
 414 #endif /* _LTTNG_TRACEPOINT_H */
 415
 416 /* The following declarations must be outside re-inclusion protection. */
 417
 418 #ifndef TRACEPOINT_EVENT
 419
 420 /*
 421  * How to use the TRACEPOINT_EVENT macro:
 422  *
 423  * An example:
 424  *
 425  * TRACEPOINT_EVENT(someproject_component, event_name,
 426  *
 427  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 428  *
 429  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 430  *             long *, arg4, size_t, arg4_len),
 431  *
 432  *      * TP_FIELDS describes the event payload layout in the trace *
 433  *
 434  *     TP_FIELDS(
 435  *         * Integer, printed in base 10 *
 436  *         ctf_integer(int, field_a, arg0)
 437  *
 438  *         * Integer, printed with 0x base 16 *
 439  *         ctf_integer_hex(unsigned long, field_d, arg1)
 440  *
 441  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 442  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 443  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 444  *
 445  *         * String, printed as UTF8-encoded string *
 446  *         ctf_string(field_e, string)
 447  *
 448  *         * Array sequence of signed integer values *
 449  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 450  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 451  *     )
 452  * )
 453  *
 454  * More detailed explanation:
 455  *
 456  * The name of the tracepoint is expressed as a tuple with the provider
 457  * and name arguments.
 458  *
 459  * The provider and name should be a proper C99 identifier.
 460  * The "provider" and "name" MUST follow these rules to ensure no
 461  * namespace clash occurs:
 462  *
 463  * For projects (applications and libraries) for which an entity
 464  * specific to the project controls the source code and thus its
 465  * tracepoints (typically with a scope larger than a single company):
 466  *
 467  * either:
 468  *   project_component, event
 469  * or:
 470  *   project, event
 471  *
 472  * Where "project" is the name of the project,
 473  *       "component" is the name of the project component (which may
 474  *       include several levels of sub-components, e.g.
 475  *       ...component_subcomponent_...) where the tracepoint is located
 476  *       (optional),
 477  *       "event" is the name of the tracepoint event.
 478  *
 479  * For projects issued from a single company wishing to advertise that
 480  * the company controls the source code and thus the tracepoints, the
 481  * "com_" prefix should be used:
 482  *
 483  * either:
 484  *   com_company_project_component, event
 485  * or:
 486  *   com_company_project, event
 487  *
 488  * Where "company" is the name of the company,
 489  *       "project" is the name of the project,
 490  *       "component" is the name of the project component (which may
 491  *       include several levels of sub-components, e.g.
 492  *       ...component_subcomponent_...) where the tracepoint is located
 493  *       (optional),
 494  *       "event" is the name of the tracepoint event.
 495  *
 496  * the provider:event identifier is limited to 127 characters.
 497  */
 498
 499 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 500         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 501         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 502
 503 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 504
 505 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 506         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 507         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 508
 509 #endif /* #ifndef TRACEPOINT_EVENT */
 510
 511 #ifndef TRACEPOINT_LOGLEVEL
 512
 513 /*
 514  * Tracepoint Loglevels
 515  *
 516  * Typical use of these loglevels:
 517  *
 518  * The loglevels go from 0 to 14. Higher numbers imply the most
 519  * verbosity (higher event throughput expected.
 520  *
 521  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 522  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 523  * debug information.
 524  *
 525  * TRACE_EMERG           0
 526  * system is unusable
 527  *
 528  * TRACE_ALERT           1
 529  * action must be taken immediately
 530  *
 531  * TRACE_CRIT            2
 532  * critical conditions
 533  *
 534  * TRACE_ERR             3
 535  * error conditions
 536  *
 537  * TRACE_WARNING         4
 538  * warning conditions
 539  *
 540  * TRACE_NOTICE          5
 541  * normal, but significant, condition
 542  *
 543  * TRACE_INFO            6
 544  * informational message
 545  *
 546  * TRACE_DEBUG_SYSTEM    7
 547  * debug information with system-level scope (set of programs)
 548  *
 549  * TRACE_DEBUG_PROGRAM   8
 550  * debug information with program-level scope (set of processes)
 551  *
 552  * TRACE_DEBUG_PROCESS   9
 553  * debug information with process-level scope (set of modules)
 554  *
 555  * TRACE_DEBUG_MODULE    10
 556  * debug information with module (executable/library) scope (set of units)
 557  *
 558  * TRACE_DEBUG_UNIT      11
 559  * debug information with compilation unit scope (set of functions)
 560  *
 561  * TRACE_DEBUG_FUNCTION  12
 562  * debug information with function-level scope
 563  *
 564  * TRACE_DEBUG_LINE      13
 565  * debug information with line-level scope (TRACEPOINT_EVENT default)
 566  *
 567  * TRACE_DEBUG           14
 568  * debug-level message (trace_printf default)
 569  *
 570  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 571  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 572  * tracepoint name. The first field is the provider name, the second
 573  * field is the name of the tracepoint, the third field is the loglevel
 574  * name.
 575  *
 576  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 577  *              < loglevel_name >)
 578  *
 579  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 580  * TRACEPOINT_LOGLEVEL.
 581  */
 582
 583 enum {
 584         TRACE_EMERG             = 0,
 585         TRACE_ALERT             = 1,
 586         TRACE_CRIT              = 2,
 587         TRACE_ERR               = 3,
 588         TRACE_WARNING           = 4,
 589         TRACE_NOTICE            = 5,
 590         TRACE_INFO              = 6,
 591         TRACE_DEBUG_SYSTEM      = 7,
 592         TRACE_DEBUG_PROGRAM     = 8,
 593         TRACE_DEBUG_PROCESS     = 9,
 594         TRACE_DEBUG_MODULE      = 10,
 595         TRACE_DEBUG_UNIT        = 11,
 596         TRACE_DEBUG_FUNCTION    = 12,
 597         TRACE_DEBUG_LINE        = 13,
 598         TRACE_DEBUG             = 14,
 599 };
 600
 601 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 602
 603 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 604
 605 #ifndef TRACEPOINT_MODEL_EMF_URI
 606
 607 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 608
 609 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */