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 <urcu/system.h>
  32 #include <dlfcn.h>      /* for dlopen */
  33 #include <string.h>     /* for memset */
  34 #include <lttng/ust-config.h>   /* for sdt */
  35 #include <lttng/ust-compiler.h>
  36
  37 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  38 #define SDT_USE_VARIADIC
  39 #include <sys/sdt.h>
  40 #else
  41 #define STAP_PROBEV(...)
  42 #endif
  43
  44 #ifdef __cplusplus
  45 extern "C" {
  46 #endif
  47
  48 #define tracepoint_enabled(provider, name) \
  49         caa_unlikely(CMM_LOAD_SHARED(__tracepoint_##provider##___##name.state))
  50
  51 #define do_tracepoint(provider, name, ...) \
  52         __tracepoint_cb_##provider##___##name(__VA_ARGS__)
  53
  54 #define tracepoint(provider, name, ...)                                     \
  55         do {                                                                \
  56                 STAP_PROBEV(provider, name, ## __VA_ARGS__);                \
  57                 if (tracepoint_enabled(provider, name))                     \
  58                         do_tracepoint(provider, name, __VA_ARGS__);         \
  59         } while (0)
  60
  61 #define TP_ARGS(...)       __VA_ARGS__
  62
  63 /*
  64  * TP_ARGS takes tuples of type, argument separated by a comma.
  65  * It can take up to 10 tuples (which means that less than 10 tuples is
  66  * fine too).
  67  * Each tuple is also separated by a comma.
  68  */
  69 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  70                 _tokena##_tokenb
  71 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  72                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  73 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  74                 _tokena##_tokenb##_tokenc
  75 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  76                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  77 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  78                 _tokena##_tokenb##_tokenc##_tokend
  79 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  80                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  81
  82 /*
  83  * _TP_EXVAR* extract the var names.
  84  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  85  */
  86 #define _TP_EXVAR0()
  87 #define _TP_EXVAR1(a)
  88 #define _TP_EXVAR2(a,b)                                         b
  89 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  90 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  91 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  92 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  93 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  94 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  95 #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
  96 #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
  97 #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
  98
  99 #define _TP_EXDATA_VAR0()                                               __tp_data
 100 #define _TP_EXDATA_VAR1(a)                                              __tp_data
 101 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
 102 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
 103 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
 104 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
 105 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
 106 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 107 #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
 108 #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
 109 #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
 110 #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
 111
 112 /*
 113  * _TP_EXPROTO* extract tuples of type, var.
 114  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 115  */
 116 #define _TP_EXPROTO0()                                          void
 117 #define _TP_EXPROTO1(a)                                         void
 118 #define _TP_EXPROTO2(a,b)                                       a b
 119 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 120 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 121 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 122 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 123 #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
 124 #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
 125 #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
 126 #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
 127 #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
 128
 129 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 130 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 131 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 132 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 133 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 134 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 135 #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
 136 #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
 137 #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
 138 #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
 139 #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
 140 #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
 141
 142 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 143 #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)
 144 #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
 145 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 146 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 147 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 148 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 149 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 150 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 151 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 152 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 153 #define _TP_PARAMS(...)                 __VA_ARGS__
 154
 155 /*
 156  * The tracepoint cb is marked always inline so we can distinguish
 157  * between caller's ip addresses within the probe using the return
 158  * address.
 159  */
 160 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 161 extern struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name;                \
 162 static inline __attribute__((always_inline, unused)) lttng_ust_notrace                  \
 163 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__));              \
 164 static                                                                                  \
 165 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 166 {                                                                                       \
 167         struct lttng_ust_tracepoint_probe *__tp_probe;                                          \
 168                                                                                         \
 169         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 170                 return;                                                                 \
 171         tp_rcu_read_lock_bp();                                                          \
 172         __tp_probe = tp_rcu_dereference_bp(__tracepoint_##_provider##___##_name.probes); \
 173         if (caa_unlikely(!__tp_probe))                                                  \
 174                 goto end;                                                               \
 175         do {                                                                            \
 176                 void (*__tp_cb)(void) = __tp_probe->func;                               \
 177                 void *__tp_data = __tp_probe->data;                                     \
 178                                                                                         \
 179                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 180                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 181         } while ((++__tp_probe)->func);                                                 \
 182 end:                                                                                    \
 183         tp_rcu_read_unlock_bp();                                                        \
 184 }                                                                                       \
 185 static inline lttng_ust_notrace                                                         \
 186 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 187                 void (*func)(void), void *data);                                        \
 188 static inline                                                                           \
 189 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 190                 void (*func)(void), void *data)                                         \
 191 {                                                                                       \
 192         __tracepoint_probe_register(name, func, data,                                   \
 193                 __tracepoint_##_provider##___##_name.signature);                        \
 194 }                                                                                       \
 195 static inline lttng_ust_notrace                                                         \
 196 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 197                 void (*func)(void), void *data);                                        \
 198 static inline                                                                           \
 199 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 200                 void (*func)(void), void *data)                                         \
 201 {                                                                                       \
 202         __tracepoint_probe_unregister(name, func, data);                                \
 203 }
 204
 205 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 206                 void *data, const char *signature);
 207 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 208                 void *data);
 209
 210 /*
 211  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 212  * shared across objects in a module/main executable.
 213  */
 214 struct lttng_ust_tracepoint_dlopen {
 215         void *liblttngust_handle;
 216
 217         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 218                 int tracepoints_count);
 219         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 220 #ifndef _LGPL_SOURCE
 221         void (*rcu_read_lock_sym_bp)(void);
 222         void (*rcu_read_unlock_sym_bp)(void);
 223         void *(*rcu_dereference_sym_bp)(void *p);
 224 #endif
 225 };
 226
 227 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 228
 229 #if defined(TRACEPOINT_DEFINE) || defined(TRACEPOINT_CREATE_PROBES)
 230
 231 /*
 232  * These weak symbols, the constructor, and destructor take care of
 233  * registering only _one_ instance of the tracepoints per shared-ojbect
 234  * (or for the whole main program).
 235  */
 236 int __tracepoint_registered
 237         __attribute__((weak, visibility("hidden")));
 238 int __tracepoint_ptrs_registered
 239         __attribute__((weak, visibility("hidden")));
 240 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 241         __attribute__((weak, visibility("hidden")));
 242
 243 #ifndef _LGPL_SOURCE
 244 static inline void lttng_ust_notrace
 245 __tracepoint__init_urcu_sym(void);
 246 static inline void
 247 __tracepoint__init_urcu_sym(void)
 248 {
 249         /*
 250          * Symbols below are needed by tracepoint call sites and probe
 251          * providers.
 252          */
 253         if (!tracepoint_dlopen.rcu_read_lock_sym_bp)
 254                 tracepoint_dlopen.rcu_read_lock_sym_bp =
 255                         URCU_FORCE_CAST(void (*)(void),
 256                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 257                                         "tp_rcu_read_lock_bp"));
 258         if (!tracepoint_dlopen.rcu_read_unlock_sym_bp)
 259                 tracepoint_dlopen.rcu_read_unlock_sym_bp =
 260                         URCU_FORCE_CAST(void (*)(void),
 261                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 262                                         "tp_rcu_read_unlock_bp"));
 263         if (!tracepoint_dlopen.rcu_dereference_sym_bp)
 264                 tracepoint_dlopen.rcu_dereference_sym_bp =
 265                         URCU_FORCE_CAST(void *(*)(void *p),
 266                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 267                                         "tp_rcu_dereference_sym_bp"));
 268 }
 269 #else
 270 static inline void lttng_ust_notrace
 271 __tracepoint__init_urcu_sym(void);
 272 static inline void
 273 __tracepoint__init_urcu_sym(void)
 274 {
 275 }
 276 #endif
 277
 278 static void lttng_ust_notrace __attribute__((constructor))
 279 __tracepoints__init(void);
 280 static void
 281 __tracepoints__init(void)
 282 {
 283         if (__tracepoint_registered++)
 284                 return;
 285
 286         if (!tracepoint_dlopen.liblttngust_handle)
 287                 tracepoint_dlopen.liblttngust_handle =
 288                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 289         if (!tracepoint_dlopen.liblttngust_handle)
 290                 return;
 291         __tracepoint__init_urcu_sym();
 292 }
 293
 294 static void lttng_ust_notrace __attribute__((destructor))
 295 __tracepoints__destroy(void);
 296 static void
 297 __tracepoints__destroy(void)
 298 {
 299         int ret;
 300
 301         if (--__tracepoint_registered)
 302                 return;
 303         if (tracepoint_dlopen.liblttngust_handle && !__tracepoint_ptrs_registered) {
 304                 ret = dlclose(tracepoint_dlopen.liblttngust_handle);
 305                 if (ret) {
 306                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 307                         abort();
 308                 }
 309                 memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
 310         }
 311 }
 312
 313 #endif
 314
 315 #ifdef TRACEPOINT_DEFINE
 316
 317 /*
 318  * These weak symbols, the constructor, and destructor take care of
 319  * registering only _one_ instance of the tracepoints per shared-ojbect
 320  * (or for the whole main program).
 321  */
 322 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 323         __attribute__((weak, visibility("hidden")));
 324 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 325         __attribute__((weak, visibility("hidden")));
 326
 327 /*
 328  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 329  * unresolved symbol that requires the provider to be linked in. When
 330  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 331  * unresolved symbol that depends on having the provider linked in,
 332  * otherwise the linker complains. This deals with use of static
 333  * libraries, ensuring that the linker does not remove the provider
 334  * object from the executable.
 335  */
 336 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 337 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 338 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 339 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 340 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 341
 342 /*
 343  * Note: to allow PIC code, we need to allow the linker to update the pointers
 344  * in the __tracepoints_ptrs section.
 345  * Therefore, this section is _not_ const (read-only).
 346  */
 347 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 348
 349 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 350         extern int __tracepoint_provider_##_provider;                           \
 351         static const char __tp_strtab_##_provider##___##_name[]                 \
 352                 __attribute__((section("__tracepoints_strings"))) =             \
 353                         #_provider ":" #_name;                                  \
 354         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 355                 __attribute__((section("__tracepoints"))) =                     \
 356                 {                                                               \
 357                         __tp_strtab_##_provider##___##_name,                    \
 358                         0,                                                      \
 359                         NULL,                                                   \
 360                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 361                         _TP_EXTRACT_STRING(_args),                              \
 362                         { },                                                    \
 363                 };                                                              \
 364         static struct lttng_ust_tracepoint *                                    \
 365                 __tracepoint_ptr_##_provider##___##_name                        \
 366                 __attribute__((used, section("__tracepoints_ptrs"))) =          \
 367                         &__tracepoint_##_provider##___##_name;
 368
 369 static void lttng_ust_notrace __attribute__((constructor))
 370 __tracepoints__ptrs_init(void);
 371 static void
 372 __tracepoints__ptrs_init(void)
 373 {
 374         if (__tracepoint_ptrs_registered++)
 375                 return;
 376         if (!tracepoint_dlopen.liblttngust_handle)
 377                 tracepoint_dlopen.liblttngust_handle =
 378                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 379         if (!tracepoint_dlopen.liblttngust_handle)
 380                 return;
 381         tracepoint_dlopen.tracepoint_register_lib =
 382                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 383                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 384                                         "tracepoint_register_lib"));
 385         tracepoint_dlopen.tracepoint_unregister_lib =
 386                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 387                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 388                                         "tracepoint_unregister_lib"));
 389         __tracepoint__init_urcu_sym();
 390         if (tracepoint_dlopen.tracepoint_register_lib) {
 391                 tracepoint_dlopen.tracepoint_register_lib(__start___tracepoints_ptrs,
 392                                 __stop___tracepoints_ptrs -
 393                                 __start___tracepoints_ptrs);
 394         }
 395 }
 396
 397 static void lttng_ust_notrace __attribute__((destructor))
 398 __tracepoints__ptrs_destroy(void);
 399 static void
 400 __tracepoints__ptrs_destroy(void)
 401 {
 402         int ret;
 403
 404         if (--__tracepoint_ptrs_registered)
 405                 return;
 406         if (tracepoint_dlopen.tracepoint_unregister_lib)
 407                 tracepoint_dlopen.tracepoint_unregister_lib(__start___tracepoints_ptrs);
 408         if (tracepoint_dlopen.liblttngust_handle && !__tracepoint_registered) {
 409                 ret = dlclose(tracepoint_dlopen.liblttngust_handle);
 410                 if (ret) {
 411                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 412                         abort();
 413                 }
 414                 memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
 415         }
 416 }
 417
 418 #else /* TRACEPOINT_DEFINE */
 419
 420 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 421
 422 #endif /* #else TRACEPOINT_DEFINE */
 423
 424 #ifdef __cplusplus
 425 }
 426 #endif
 427
 428 #endif /* _LTTNG_TRACEPOINT_H */
 429
 430 /* The following declarations must be outside re-inclusion protection. */
 431
 432 #ifndef TRACEPOINT_EVENT
 433
 434 /*
 435  * How to use the TRACEPOINT_EVENT macro:
 436  *
 437  * An example:
 438  *
 439  * TRACEPOINT_EVENT(someproject_component, event_name,
 440  *
 441  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 442  *
 443  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 444  *             long *, arg4, size_t, arg4_len),
 445  *
 446  *      * TP_FIELDS describes the event payload layout in the trace *
 447  *
 448  *     TP_FIELDS(
 449  *         * Integer, printed in base 10 *
 450  *         ctf_integer(int, field_a, arg0)
 451  *
 452  *         * Integer, printed with 0x base 16 *
 453  *         ctf_integer_hex(unsigned long, field_d, arg1)
 454  *
 455  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 456  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 457  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 458  *
 459  *         * String, printed as UTF8-encoded string *
 460  *         ctf_string(field_e, string)
 461  *
 462  *         * Array sequence of signed integer values *
 463  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 464  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 465  *     )
 466  * )
 467  *
 468  * More detailed explanation:
 469  *
 470  * The name of the tracepoint is expressed as a tuple with the provider
 471  * and name arguments.
 472  *
 473  * The provider and name should be a proper C99 identifier.
 474  * The "provider" and "name" MUST follow these rules to ensure no
 475  * namespace clash occurs:
 476  *
 477  * For projects (applications and libraries) for which an entity
 478  * specific to the project controls the source code and thus its
 479  * tracepoints (typically with a scope larger than a single company):
 480  *
 481  * either:
 482  *   project_component, event
 483  * or:
 484  *   project, event
 485  *
 486  * Where "project" is the name of the project,
 487  *       "component" is the name of the project component (which may
 488  *       include several levels of sub-components, e.g.
 489  *       ...component_subcomponent_...) where the tracepoint is located
 490  *       (optional),
 491  *       "event" is the name of the tracepoint event.
 492  *
 493  * For projects issued from a single company wishing to advertise that
 494  * the company controls the source code and thus the tracepoints, the
 495  * "com_" prefix should be used:
 496  *
 497  * either:
 498  *   com_company_project_component, event
 499  * or:
 500  *   com_company_project, event
 501  *
 502  * Where "company" is the name of the company,
 503  *       "project" is the name of the project,
 504  *       "component" is the name of the project component (which may
 505  *       include several levels of sub-components, e.g.
 506  *       ...component_subcomponent_...) where the tracepoint is located
 507  *       (optional),
 508  *       "event" is the name of the tracepoint event.
 509  *
 510  * the provider:event identifier is limited to 127 characters.
 511  */
 512
 513 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 514         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 515         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 516
 517 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 518
 519 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 520         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 521         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 522
 523 #endif /* #ifndef TRACEPOINT_EVENT */
 524
 525 #ifndef TRACEPOINT_LOGLEVEL
 526
 527 /*
 528  * Tracepoint Loglevels
 529  *
 530  * Typical use of these loglevels:
 531  *
 532  * The loglevels go from 0 to 14. Higher numbers imply the most
 533  * verbosity (higher event throughput expected.
 534  *
 535  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 536  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 537  * debug information.
 538  *
 539  * TRACE_EMERG           0
 540  * system is unusable
 541  *
 542  * TRACE_ALERT           1
 543  * action must be taken immediately
 544  *
 545  * TRACE_CRIT            2
 546  * critical conditions
 547  *
 548  * TRACE_ERR             3
 549  * error conditions
 550  *
 551  * TRACE_WARNING         4
 552  * warning conditions
 553  *
 554  * TRACE_NOTICE          5
 555  * normal, but significant, condition
 556  *
 557  * TRACE_INFO            6
 558  * informational message
 559  *
 560  * TRACE_DEBUG_SYSTEM    7
 561  * debug information with system-level scope (set of programs)
 562  *
 563  * TRACE_DEBUG_PROGRAM   8
 564  * debug information with program-level scope (set of processes)
 565  *
 566  * TRACE_DEBUG_PROCESS   9
 567  * debug information with process-level scope (set of modules)
 568  *
 569  * TRACE_DEBUG_MODULE    10
 570  * debug information with module (executable/library) scope (set of units)
 571  *
 572  * TRACE_DEBUG_UNIT      11
 573  * debug information with compilation unit scope (set of functions)
 574  *
 575  * TRACE_DEBUG_FUNCTION  12
 576  * debug information with function-level scope
 577  *
 578  * TRACE_DEBUG_LINE      13
 579  * debug information with line-level scope (TRACEPOINT_EVENT default)
 580  *
 581  * TRACE_DEBUG           14
 582  * debug-level message
 583  *
 584  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 585  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 586  * tracepoint name. The first field is the provider name, the second
 587  * field is the name of the tracepoint, the third field is the loglevel
 588  * name.
 589  *
 590  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 591  *              < loglevel_name >)
 592  *
 593  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 594  * TRACEPOINT_LOGLEVEL.
 595  */
 596
 597 enum {
 598         TRACE_EMERG             = 0,
 599         TRACE_ALERT             = 1,
 600         TRACE_CRIT              = 2,
 601         TRACE_ERR               = 3,
 602         TRACE_WARNING           = 4,
 603         TRACE_NOTICE            = 5,
 604         TRACE_INFO              = 6,
 605         TRACE_DEBUG_SYSTEM      = 7,
 606         TRACE_DEBUG_PROGRAM     = 8,
 607         TRACE_DEBUG_PROCESS     = 9,
 608         TRACE_DEBUG_MODULE      = 10,
 609         TRACE_DEBUG_UNIT        = 11,
 610         TRACE_DEBUG_FUNCTION    = 12,
 611         TRACE_DEBUG_LINE        = 13,
 612         TRACE_DEBUG             = 14,
 613 };
 614
 615 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 616
 617 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 618
 619 #ifndef TRACEPOINT_MODEL_EMF_URI
 620
 621 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 622
 623 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */