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