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