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_enabled(provider, name) \
  50         caa_unlikely(CMM_LOAD_SHARED(__tracepoint_##provider##___##name.state))
  51
  52 #define do_tracepoint(provider, name, ...) \
  53         __tracepoint_cb_##provider##___##name(__VA_ARGS__)
  54
  55 #define tracepoint(provider, name, ...)                                     \
  56         do {                                                                \
  57                 LTTNG_STAP_PROBEV(provider, name, ## __VA_ARGS__);          \
  58                 if (tracepoint_enabled(provider, name))                     \
  59                         do_tracepoint(provider, name, __VA_ARGS__);         \
  60         } while (0)
  61
  62 #define TP_ARGS(...)       __VA_ARGS__
  63
  64 /*
  65  * TP_ARGS takes tuples of type, argument separated by a comma.
  66  * It can take up to 10 tuples (which means that less than 10 tuples is
  67  * fine too).
  68  * Each tuple is also separated by a comma.
  69  */
  70 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  71                 _tokena##_tokenb
  72 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  73                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  74 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  75                 _tokena##_tokenb##_tokenc
  76 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  77                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  78 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  79                 _tokena##_tokenb##_tokenc##_tokend
  80 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  81                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  82
  83 /*
  84  * _TP_EXVAR* extract the var names.
  85  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  86  */
  87 #define _TP_EXVAR0()
  88 #define _TP_EXVAR1(a)
  89 #define _TP_EXVAR2(a,b)                                         b
  90 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  91 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  92 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  93 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  94 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  95 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  96 #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
  97 #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
  98 #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
  99
 100 #define _TP_EXDATA_VAR0()                                               __tp_data
 101 #define _TP_EXDATA_VAR1(a)                                              __tp_data
 102 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
 103 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
 104 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
 105 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
 106 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
 107 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 108 #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
 109 #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
 110 #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
 111 #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
 112
 113 /*
 114  * _TP_EXPROTO* extract tuples of type, var.
 115  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 116  */
 117 #define _TP_EXPROTO0()                                          void
 118 #define _TP_EXPROTO1(a)                                         void
 119 #define _TP_EXPROTO2(a,b)                                       a b
 120 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 121 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 122 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 123 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 124 #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
 125 #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
 126 #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
 127 #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
 128 #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
 129
 130 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 131 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 132 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 133 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 134 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 135 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 136 #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
 137 #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
 138 #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
 139 #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
 140 #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
 141 #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
 142
 143 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 144 #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)
 145 #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
 146 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 147 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 148 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 149 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 150 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 151 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 152 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 153 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 154 #define _TP_PARAMS(...)                 __VA_ARGS__
 155
 156 /*
 157  * The tracepoint cb is marked always inline so we can distinguish
 158  * between caller's ip addresses within the probe using the return
 159  * address.
 160  */
 161 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 162 extern struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name;                \
 163 static inline __attribute__((always_inline, unused)) lttng_ust_notrace                  \
 164 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__));              \
 165 static                                                                                  \
 166 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 167 {                                                                                       \
 168         struct lttng_ust_tracepoint_probe *__tp_probe;                                          \
 169                                                                                         \
 170         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 171                 return;                                                                 \
 172         tp_rcu_read_lock_bp();                                                          \
 173         __tp_probe = tp_rcu_dereference_bp(__tracepoint_##_provider##___##_name.probes); \
 174         if (caa_unlikely(!__tp_probe))                                                  \
 175                 goto end;                                                               \
 176         do {                                                                            \
 177                 void (*__tp_cb)(void) = __tp_probe->func;                               \
 178                 void *__tp_data = __tp_probe->data;                                     \
 179                                                                                         \
 180                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 181                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 182         } while ((++__tp_probe)->func);                                                 \
 183 end:                                                                                    \
 184         tp_rcu_read_unlock_bp();                                                        \
 185 }                                                                                       \
 186 static inline lttng_ust_notrace                                                         \
 187 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 188                 void (*func)(void), void *data);                                        \
 189 static inline                                                                           \
 190 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 191                 void (*func)(void), void *data)                                         \
 192 {                                                                                       \
 193         __tracepoint_probe_register(name, func, data,                                   \
 194                 __tracepoint_##_provider##___##_name.signature);                        \
 195 }                                                                                       \
 196 static inline lttng_ust_notrace                                                         \
 197 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 198                 void (*func)(void), void *data);                                        \
 199 static inline                                                                           \
 200 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 201                 void (*func)(void), void *data)                                         \
 202 {                                                                                       \
 203         __tracepoint_probe_unregister(name, func, data);                                \
 204 }
 205
 206 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 207                 void *data, const char *signature);
 208 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 209                 void *data);
 210
 211 /*
 212  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 213  * shared across objects in a module/main executable.
 214  */
 215 struct lttng_ust_tracepoint_dlopen {
 216         void *liblttngust_handle;
 217
 218         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 219                 int tracepoints_count);
 220         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 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 };
 225
 226 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 227 extern struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr;
 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  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 244  * 4.8 and prior does not have the same behavior for symbol scoping on
 245  * 32-bit powerpc depending on the object size: symbols for objects of 8
 246  * bytes or less have the same address throughout a module, whereas they
 247  * have different addresses between compile units for objects larger
 248  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 249  * scoping match that of the other weak hidden symbols found in this
 250  * header.
 251  */
 252 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 253         __attribute__((weak, visibility("hidden")));
 254
 255 #ifndef _LGPL_SOURCE
 256 static inline void lttng_ust_notrace
 257 __tracepoint__init_urcu_sym(void);
 258 static inline void
 259 __tracepoint__init_urcu_sym(void)
 260 {
 261         if (!tracepoint_dlopen_ptr)
 262                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 263         /*
 264          * Symbols below are needed by tracepoint call sites and probe
 265          * providers.
 266          */
 267         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym_bp)
 268                 tracepoint_dlopen_ptr->rcu_read_lock_sym_bp =
 269                         URCU_FORCE_CAST(void (*)(void),
 270                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 271                                         "tp_rcu_read_lock_bp"));
 272         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym_bp)
 273                 tracepoint_dlopen_ptr->rcu_read_unlock_sym_bp =
 274                         URCU_FORCE_CAST(void (*)(void),
 275                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 276                                         "tp_rcu_read_unlock_bp"));
 277         if (!tracepoint_dlopen_ptr->rcu_dereference_sym_bp)
 278                 tracepoint_dlopen_ptr->rcu_dereference_sym_bp =
 279                         URCU_FORCE_CAST(void *(*)(void *p),
 280                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 281                                         "tp_rcu_dereference_sym_bp"));
 282 }
 283 #else
 284 static inline void lttng_ust_notrace
 285 __tracepoint__init_urcu_sym(void);
 286 static inline void
 287 __tracepoint__init_urcu_sym(void)
 288 {
 289 }
 290 #endif
 291
 292 static void lttng_ust_notrace __attribute__((constructor))
 293 __tracepoints__init(void);
 294 static void
 295 __tracepoints__init(void)
 296 {
 297         if (__tracepoint_registered++)
 298                 return;
 299
 300         if (!tracepoint_dlopen_ptr)
 301                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 302         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 303                 tracepoint_dlopen_ptr->liblttngust_handle =
 304                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 305         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 306                 return;
 307         __tracepoint__init_urcu_sym();
 308 }
 309
 310 static void lttng_ust_notrace __attribute__((destructor))
 311 __tracepoints__destroy(void);
 312 static void
 313 __tracepoints__destroy(void)
 314 {
 315         int ret;
 316
 317         if (--__tracepoint_registered)
 318                 return;
 319         if (!tracepoint_dlopen_ptr)
 320                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 321         if (tracepoint_dlopen_ptr->liblttngust_handle && !__tracepoint_ptrs_registered) {
 322                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 323                 if (ret) {
 324                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 325                         abort();
 326                 }
 327                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 328         }
 329 }
 330
 331 #endif
 332
 333 #ifdef TRACEPOINT_DEFINE
 334
 335 /*
 336  * These weak symbols, the constructor, and destructor take care of
 337  * registering only _one_ instance of the tracepoints per shared-ojbect
 338  * (or for the whole main program).
 339  */
 340 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 341         __attribute__((weak, visibility("hidden")));
 342 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 343         __attribute__((weak, visibility("hidden")));
 344
 345 /*
 346  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 347  * unresolved symbol that requires the provider to be linked in. When
 348  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 349  * unresolved symbol that depends on having the provider linked in,
 350  * otherwise the linker complains. This deals with use of static
 351  * libraries, ensuring that the linker does not remove the provider
 352  * object from the executable.
 353  */
 354 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 355 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 356 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 357 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 358 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 359
 360 /*
 361  * Note: to allow PIC code, we need to allow the linker to update the pointers
 362  * in the __tracepoints_ptrs section.
 363  * Therefore, this section is _not_ const (read-only).
 364  */
 365 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 366
 367 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 368         extern int __tracepoint_provider_##_provider;                           \
 369         static const char __tp_strtab_##_provider##___##_name[]                 \
 370                 __attribute__((section("__tracepoints_strings"))) =             \
 371                         #_provider ":" #_name;                                  \
 372         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 373                 __attribute__((section("__tracepoints"))) =                     \
 374                 {                                                               \
 375                         __tp_strtab_##_provider##___##_name,                    \
 376                         0,                                                      \
 377                         NULL,                                                   \
 378                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 379                         _TP_EXTRACT_STRING(_args),                              \
 380                         { },                                                    \
 381                 };                                                              \
 382         static struct lttng_ust_tracepoint *                                    \
 383                 __tracepoint_ptr_##_provider##___##_name                        \
 384                 __attribute__((used, section("__tracepoints_ptrs"))) =          \
 385                         &__tracepoint_##_provider##___##_name;
 386
 387 static void lttng_ust_notrace __attribute__((constructor))
 388 __tracepoints__ptrs_init(void);
 389 static void
 390 __tracepoints__ptrs_init(void)
 391 {
 392         if (__tracepoint_ptrs_registered++)
 393                 return;
 394         if (!tracepoint_dlopen_ptr)
 395                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 396         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 397                 tracepoint_dlopen_ptr->liblttngust_handle =
 398                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 399         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 400                 return;
 401         tracepoint_dlopen_ptr->tracepoint_register_lib =
 402                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 403                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 404                                         "tracepoint_register_lib"));
 405         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 406                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 407                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 408                                         "tracepoint_unregister_lib"));
 409         __tracepoint__init_urcu_sym();
 410         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 411                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 412                                 __stop___tracepoints_ptrs -
 413                                 __start___tracepoints_ptrs);
 414         }
 415 }
 416
 417 static void lttng_ust_notrace __attribute__((destructor))
 418 __tracepoints__ptrs_destroy(void);
 419 static void
 420 __tracepoints__ptrs_destroy(void)
 421 {
 422         int ret;
 423
 424         if (--__tracepoint_ptrs_registered)
 425                 return;
 426         if (!tracepoint_dlopen_ptr)
 427                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 428         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 429                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 430         if (tracepoint_dlopen_ptr->liblttngust_handle && !__tracepoint_registered) {
 431                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 432                 if (ret) {
 433                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 434                         abort();
 435                 }
 436                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 437         }
 438 }
 439
 440 #else /* TRACEPOINT_DEFINE */
 441
 442 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 443
 444 #endif /* #else TRACEPOINT_DEFINE */
 445
 446 #ifdef __cplusplus
 447 }
 448 #endif
 449
 450 #endif /* _LTTNG_TRACEPOINT_H */
 451
 452 /* The following declarations must be outside re-inclusion protection. */
 453
 454 #ifndef TRACEPOINT_EVENT
 455
 456 /*
 457  * How to use the TRACEPOINT_EVENT macro:
 458  *
 459  * An example:
 460  *
 461  * TRACEPOINT_EVENT(someproject_component, event_name,
 462  *
 463  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 464  *
 465  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 466  *             long *, arg4, size_t, arg4_len),
 467  *
 468  *      * TP_FIELDS describes the event payload layout in the trace *
 469  *
 470  *     TP_FIELDS(
 471  *         * Integer, printed in base 10 *
 472  *         ctf_integer(int, field_a, arg0)
 473  *
 474  *         * Integer, printed with 0x base 16 *
 475  *         ctf_integer_hex(unsigned long, field_d, arg1)
 476  *
 477  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 478  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 479  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 480  *
 481  *         * String, printed as UTF8-encoded string *
 482  *         ctf_string(field_e, string)
 483  *
 484  *         * Array sequence of signed integer values *
 485  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 486  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 487  *     )
 488  * )
 489  *
 490  * More detailed explanation:
 491  *
 492  * The name of the tracepoint is expressed as a tuple with the provider
 493  * and name arguments.
 494  *
 495  * The provider and name should be a proper C99 identifier.
 496  * The "provider" and "name" MUST follow these rules to ensure no
 497  * namespace clash occurs:
 498  *
 499  * For projects (applications and libraries) for which an entity
 500  * specific to the project controls the source code and thus its
 501  * tracepoints (typically with a scope larger than a single company):
 502  *
 503  * either:
 504  *   project_component, event
 505  * or:
 506  *   project, event
 507  *
 508  * Where "project" is the name of the project,
 509  *       "component" is the name of the project component (which may
 510  *       include several levels of sub-components, e.g.
 511  *       ...component_subcomponent_...) where the tracepoint is located
 512  *       (optional),
 513  *       "event" is the name of the tracepoint event.
 514  *
 515  * For projects issued from a single company wishing to advertise that
 516  * the company controls the source code and thus the tracepoints, the
 517  * "com_" prefix should be used:
 518  *
 519  * either:
 520  *   com_company_project_component, event
 521  * or:
 522  *   com_company_project, event
 523  *
 524  * Where "company" is the name of the company,
 525  *       "project" is the name of the project,
 526  *       "component" is the name of the project component (which may
 527  *       include several levels of sub-components, e.g.
 528  *       ...component_subcomponent_...) where the tracepoint is located
 529  *       (optional),
 530  *       "event" is the name of the tracepoint event.
 531  *
 532  * the provider:event identifier is limited to 127 characters.
 533  */
 534
 535 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 536         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 537         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 538
 539 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 540
 541 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 542         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 543         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 544
 545 #endif /* #ifndef TRACEPOINT_EVENT */
 546
 547 #ifndef TRACEPOINT_LOGLEVEL
 548
 549 /*
 550  * Tracepoint Loglevels
 551  *
 552  * Typical use of these loglevels:
 553  *
 554  * The loglevels go from 0 to 14. Higher numbers imply the most
 555  * verbosity (higher event throughput expected.
 556  *
 557  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 558  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 559  * debug information.
 560  *
 561  * TRACE_EMERG           0
 562  * system is unusable
 563  *
 564  * TRACE_ALERT           1
 565  * action must be taken immediately
 566  *
 567  * TRACE_CRIT            2
 568  * critical conditions
 569  *
 570  * TRACE_ERR             3
 571  * error conditions
 572  *
 573  * TRACE_WARNING         4
 574  * warning conditions
 575  *
 576  * TRACE_NOTICE          5
 577  * normal, but significant, condition
 578  *
 579  * TRACE_INFO            6
 580  * informational message
 581  *
 582  * TRACE_DEBUG_SYSTEM    7
 583  * debug information with system-level scope (set of programs)
 584  *
 585  * TRACE_DEBUG_PROGRAM   8
 586  * debug information with program-level scope (set of processes)
 587  *
 588  * TRACE_DEBUG_PROCESS   9
 589  * debug information with process-level scope (set of modules)
 590  *
 591  * TRACE_DEBUG_MODULE    10
 592  * debug information with module (executable/library) scope (set of units)
 593  *
 594  * TRACE_DEBUG_UNIT      11
 595  * debug information with compilation unit scope (set of functions)
 596  *
 597  * TRACE_DEBUG_FUNCTION  12
 598  * debug information with function-level scope
 599  *
 600  * TRACE_DEBUG_LINE      13
 601  * debug information with line-level scope (TRACEPOINT_EVENT default)
 602  *
 603  * TRACE_DEBUG           14
 604  * debug-level message
 605  *
 606  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 607  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 608  * tracepoint name. The first field is the provider name, the second
 609  * field is the name of the tracepoint, the third field is the loglevel
 610  * name.
 611  *
 612  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 613  *              < loglevel_name >)
 614  *
 615  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 616  * TRACEPOINT_LOGLEVEL.
 617  */
 618
 619 enum {
 620         TRACE_EMERG             = 0,
 621         TRACE_ALERT             = 1,
 622         TRACE_CRIT              = 2,
 623         TRACE_ERR               = 3,
 624         TRACE_WARNING           = 4,
 625         TRACE_NOTICE            = 5,
 626         TRACE_INFO              = 6,
 627         TRACE_DEBUG_SYSTEM      = 7,
 628         TRACE_DEBUG_PROGRAM     = 8,
 629         TRACE_DEBUG_PROCESS     = 9,
 630         TRACE_DEBUG_MODULE      = 10,
 631         TRACE_DEBUG_UNIT        = 11,
 632         TRACE_DEBUG_FUNCTION    = 12,
 633         TRACE_DEBUG_LINE        = 13,
 634         TRACE_DEBUG             = 14,
 635 };
 636
 637 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 638
 639 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 640
 641 #ifndef TRACEPOINT_MODEL_EMF_URI
 642
 643 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 644
 645 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */