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