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 /*
 230  * These weak symbols, the constructor, and destructor take care of
 231  * registering only _one_ instance of the tracepoints per shared-ojbect
 232  * (or for the whole main program).
 233  */
 234 int __tracepoint_registered
 235         __attribute__((weak, visibility("hidden")));
 236 int __tracepoint_ptrs_registered
 237         __attribute__((weak, visibility("hidden")));
 238 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 239         __attribute__((weak, visibility("hidden")));
 240 /*
 241  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 242  * 4.8 and prior does not have the same behavior for symbol scoping on
 243  * 32-bit powerpc depending on the object size: symbols for objects of 8
 244  * bytes or less have the same address throughout a module, whereas they
 245  * have different addresses between compile units for objects larger
 246  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 247  * scoping match that of the other weak hidden symbols found in this
 248  * header.
 249  */
 250 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 251         __attribute__((weak, visibility("hidden")));
 252
 253 /*
 254  * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared
 255  * across objects in a module/main executable. The callbacks are used to
 256  * control and check if the destructors should be executed.
 257  */
 258 struct lttng_ust_tracepoint_destructors_syms {
 259         int *old_tracepoint_disable_destructors;
 260         void (*tracepoint_disable_destructors)(void);
 261         int (*tracepoint_get_destructors_state)(void);
 262 };
 263
 264 extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms;
 265 extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr;
 266
 267 struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms
 268         __attribute__((weak, visibility("hidden")));
 269 struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr
 270         __attribute__((weak, visibility("hidden")));
 271
 272 static inline void tracepoint_disable_destructors(void)
 273 {
 274         if (!tracepoint_dlopen_ptr)
 275                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 276         if (!tracepoint_destructors_syms_ptr)
 277                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 278         if (tracepoint_dlopen_ptr->liblttngust_handle
 279                         && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors)
 280                 tracepoint_destructors_syms_ptr->tracepoint_disable_destructors();
 281         *tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors = 1;
 282 }
 283
 284 #ifndef _LGPL_SOURCE
 285 static inline void lttng_ust_notrace
 286 __tracepoint__init_urcu_sym(void);
 287 static inline void
 288 __tracepoint__init_urcu_sym(void)
 289 {
 290         if (!tracepoint_dlopen_ptr)
 291                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 292         /*
 293          * Symbols below are needed by tracepoint call sites and probe
 294          * providers.
 295          */
 296         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym_bp)
 297                 tracepoint_dlopen_ptr->rcu_read_lock_sym_bp =
 298                         URCU_FORCE_CAST(void (*)(void),
 299                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 300                                         "tp_rcu_read_lock_bp"));
 301         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym_bp)
 302                 tracepoint_dlopen_ptr->rcu_read_unlock_sym_bp =
 303                         URCU_FORCE_CAST(void (*)(void),
 304                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 305                                         "tp_rcu_read_unlock_bp"));
 306         if (!tracepoint_dlopen_ptr->rcu_dereference_sym_bp)
 307                 tracepoint_dlopen_ptr->rcu_dereference_sym_bp =
 308                         URCU_FORCE_CAST(void *(*)(void *p),
 309                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 310                                         "tp_rcu_dereference_sym_bp"));
 311 }
 312 #else
 313 static inline void lttng_ust_notrace
 314 __tracepoint__init_urcu_sym(void);
 315 static inline void
 316 __tracepoint__init_urcu_sym(void)
 317 {
 318 }
 319 #endif
 320
 321 static void lttng_ust_notrace __attribute__((constructor))
 322 __tracepoints__init(void);
 323 static void
 324 __tracepoints__init(void)
 325 {
 326         if (__tracepoint_registered++) {
 327                 if (!tracepoint_dlopen_ptr->liblttngust_handle)
 328                         return;
 329                 __tracepoint__init_urcu_sym();
 330                 return;
 331         }
 332
 333         if (!tracepoint_dlopen_ptr)
 334                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 335         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 336                 tracepoint_dlopen_ptr->liblttngust_handle =
 337                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 338         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 339                 return;
 340         __tracepoint__init_urcu_sym();
 341 }
 342
 343 static void lttng_ust_notrace __attribute__((destructor))
 344 __tracepoints__destroy(void);
 345 static void
 346 __tracepoints__destroy(void)
 347 {
 348         int ret;
 349
 350         if (--__tracepoint_registered)
 351                 return;
 352         if (!tracepoint_dlopen_ptr)
 353                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 354         if (!tracepoint_destructors_syms_ptr)
 355                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 356         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 357                 return;
 358         if (__tracepoint_ptrs_registered)
 359                 return;
 360         /*
 361          * Lookup if destructors must be executed using the new method.
 362          */
 363         if (tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 364                 && !tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()) {
 365                 /*
 366                  * The tracepoint_get_destructors_state symbol was found with
 367                  * dlsym but its returned value is 0 meaning that destructors
 368                  * must not be executed.
 369                  */
 370                 return;
 371         }
 372         /*
 373          * Lookup if destructors must be executed using the old method.
 374          */
 375         if (tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors
 376                 && *tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors) {
 377                 /*
 378                  * The old_tracepoint_disable_destructors symbol was found with
 379                  * dlsym but its value is 1 meaning that destructors must not
 380                  * be executed.
 381                  */
 382                 return;
 383         }
 384
 385         ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 386         if (ret) {
 387                 fprintf(stderr, "Error (%d) in dlclose\n", ret);
 388                 abort();
 389         }
 390         memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 391 }
 392
 393 #ifdef TRACEPOINT_DEFINE
 394
 395 /*
 396  * These weak symbols, the constructor, and destructor take care of
 397  * registering only _one_ instance of the tracepoints per shared-ojbect
 398  * (or for the whole main program).
 399  */
 400 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 401         __attribute__((weak, visibility("hidden")));
 402 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 403         __attribute__((weak, visibility("hidden")));
 404
 405 /*
 406  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 407  * unresolved symbol that requires the provider to be linked in. When
 408  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 409  * unresolved symbol that depends on having the provider linked in,
 410  * otherwise the linker complains. This deals with use of static
 411  * libraries, ensuring that the linker does not remove the provider
 412  * object from the executable.
 413  */
 414 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 415 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 416 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 417 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 418 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 419
 420 /*
 421  * Note: to allow PIC code, we need to allow the linker to update the pointers
 422  * in the __tracepoints_ptrs section.
 423  * Therefore, this section is _not_ const (read-only).
 424  */
 425 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 426
 427 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 428         extern int __tracepoint_provider_##_provider;                           \
 429         static const char __tp_strtab_##_provider##___##_name[]                 \
 430                 __attribute__((section("__tracepoints_strings"))) =             \
 431                         #_provider ":" #_name;                                  \
 432         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 433                 __attribute__((section("__tracepoints"))) =                     \
 434                 {                                                               \
 435                         __tp_strtab_##_provider##___##_name,                    \
 436                         0,                                                      \
 437                         NULL,                                                   \
 438                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 439                         _TP_EXTRACT_STRING(_args),                              \
 440                         { },                                                    \
 441                 };                                                              \
 442         static struct lttng_ust_tracepoint *                                    \
 443                 __tracepoint_ptr_##_provider##___##_name                        \
 444                 __attribute__((used, section("__tracepoints_ptrs"))) =          \
 445                         &__tracepoint_##_provider##___##_name;
 446
 447 static void lttng_ust_notrace __attribute__((constructor))
 448 __tracepoints__ptrs_init(void);
 449 static void
 450 __tracepoints__ptrs_init(void)
 451 {
 452         if (__tracepoint_ptrs_registered++)
 453                 return;
 454         if (!tracepoint_dlopen_ptr)
 455                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 456         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 457                 tracepoint_dlopen_ptr->liblttngust_handle =
 458                         dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 459         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 460                 return;
 461         if (!tracepoint_destructors_syms_ptr)
 462                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 463         tracepoint_dlopen_ptr->tracepoint_register_lib =
 464                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 465                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 466                                         "tracepoint_register_lib"));
 467         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 468                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 469                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 470                                         "tracepoint_unregister_lib"));
 471         tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors =
 472                 URCU_FORCE_CAST(int *,
 473                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 474                                         "__tracepoints__disable_destructors"));
 475         tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
 476                 URCU_FORCE_CAST(void (*)(void),
 477                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 478                                         "tp_disable_destructors"));
 479         tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state =
 480                 URCU_FORCE_CAST(int (*)(void),
 481                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 482                                         "tp_get_destructors_state"));
 483         __tracepoint__init_urcu_sym();
 484         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 485                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 486                                 __stop___tracepoints_ptrs -
 487                                 __start___tracepoints_ptrs);
 488         }
 489 }
 490
 491 static void lttng_ust_notrace __attribute__((destructor))
 492 __tracepoints__ptrs_destroy(void);
 493 static void
 494 __tracepoints__ptrs_destroy(void)
 495 {
 496         int ret;
 497
 498         if (--__tracepoint_ptrs_registered)
 499                 return;
 500         if (!tracepoint_dlopen_ptr)
 501                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 502         if (!tracepoint_destructors_syms_ptr)
 503                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 504         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 505                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 506         if (tracepoint_dlopen_ptr->liblttngust_handle
 507                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 508                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
 509                         && !__tracepoint_ptrs_registered) {
 510                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 511                 if (ret) {
 512                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 513                         abort();
 514                 }
 515                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 516         }
 517 }
 518
 519 #else /* TRACEPOINT_DEFINE */
 520
 521 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 522
 523 #endif /* #else TRACEPOINT_DEFINE */
 524
 525 #ifdef __cplusplus
 526 }
 527 #endif
 528
 529 #endif /* _LTTNG_TRACEPOINT_H */
 530
 531 /* The following declarations must be outside re-inclusion protection. */
 532
 533 #ifndef TRACEPOINT_ENUM
 534
 535 /*
 536  * Tracepoint Enumerations
 537  *
 538  * The enumeration is a mapping between an integer, or range of integers, and
 539  * a string. It can be used to have a more compact trace in cases where the
 540  * possible values for a field are limited:
 541  *
 542  * An example:
 543  *
 544  * TRACEPOINT_ENUM(someproject_component, enumname,
 545  *      TP_ENUM_VALUES(
 546  *              ctf_enum_value("even", 0)
 547  *              ctf_enum_value("uneven", 1)
 548  *              ctf_enum_range("twoto4", 2, 4)
 549  *              ctf_enum_value("five", 5)
 550  *      )
 551  * )
 552  *
 553  * Where "someproject_component" is the name of the component this enumeration
 554  * belongs to and "enumname" identifies this enumeration. Inside the
 555  * TP_ENUM_VALUES macro is the actual mapping. Each string value can map
 556  * to either a single value with ctf_enum_value or a range of values
 557  * with ctf_enum_range.
 558  *
 559  * Enumeration ranges may overlap, but the behavior is implementation-defined,
 560  * each trace reader will handle overlapping as it wishes.
 561  *
 562  * That enumeration can then be used in a field inside the TP_FIELD macro using
 563  * the following line:
 564  *
 565  * ctf_enum(someproject_component, enumname, enumtype, enumfield, enumval)
 566  *
 567  * Where "someproject_component" and "enumname" match those in the
 568  * TRACEPOINT_ENUM, "enumtype" is a signed or unsigned integer type
 569  * backing the enumeration, "enumfield" is the name of the field and
 570  * "enumval" is the value.
 571  */
 572
 573 #define TRACEPOINT_ENUM(provider, name, values)
 574
 575 #endif /* #ifndef TRACEPOINT_ENUM */
 576
 577 #ifndef TRACEPOINT_EVENT
 578
 579 /*
 580  * How to use the TRACEPOINT_EVENT macro:
 581  *
 582  * An example:
 583  *
 584  * TRACEPOINT_EVENT(someproject_component, event_name,
 585  *
 586  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 587  *
 588  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 589  *             long *, arg4, size_t, arg4_len),
 590  *
 591  *      * TP_FIELDS describes the event payload layout in the trace *
 592  *
 593  *     TP_FIELDS(
 594  *         * Integer, printed in base 10 *
 595  *         ctf_integer(int, field_a, arg0)
 596  *
 597  *         * Integer, printed with 0x base 16 *
 598  *         ctf_integer_hex(unsigned long, field_d, arg1)
 599  *
 600  *         * Enumeration *
 601  *         ctf_enum(someproject_component, enum_name, int, field_e, arg0)
 602  *
 603  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 604  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 605  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 606  *
 607  *         * String, printed as UTF8-encoded string *
 608  *         ctf_string(field_e, string)
 609  *
 610  *         * Array sequence of signed integer values *
 611  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 612  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 613  *     )
 614  * )
 615  *
 616  * More detailed explanation:
 617  *
 618  * The name of the tracepoint is expressed as a tuple with the provider
 619  * and name arguments.
 620  *
 621  * The provider and name should be a proper C99 identifier.
 622  * The "provider" and "name" MUST follow these rules to ensure no
 623  * namespace clash occurs:
 624  *
 625  * For projects (applications and libraries) for which an entity
 626  * specific to the project controls the source code and thus its
 627  * tracepoints (typically with a scope larger than a single company):
 628  *
 629  * either:
 630  *   project_component, event
 631  * or:
 632  *   project, event
 633  *
 634  * Where "project" is the name of the project,
 635  *       "component" is the name of the project component (which may
 636  *       include several levels of sub-components, e.g.
 637  *       ...component_subcomponent_...) where the tracepoint is located
 638  *       (optional),
 639  *       "event" is the name of the tracepoint event.
 640  *
 641  * For projects issued from a single company wishing to advertise that
 642  * the company controls the source code and thus the tracepoints, the
 643  * "com_" prefix should be used:
 644  *
 645  * either:
 646  *   com_company_project_component, event
 647  * or:
 648  *   com_company_project, event
 649  *
 650  * Where "company" is the name of the company,
 651  *       "project" is the name of the project,
 652  *       "component" is the name of the project component (which may
 653  *       include several levels of sub-components, e.g.
 654  *       ...component_subcomponent_...) where the tracepoint is located
 655  *       (optional),
 656  *       "event" is the name of the tracepoint event.
 657  *
 658  * the provider:event identifier is limited to 127 characters.
 659  */
 660
 661 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 662         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 663         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 664
 665 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 666
 667 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 668         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 669         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 670
 671 #endif /* #ifndef TRACEPOINT_EVENT */
 672
 673 #ifndef TRACEPOINT_LOGLEVEL
 674
 675 /*
 676  * Tracepoint Loglevels
 677  *
 678  * Typical use of these loglevels:
 679  *
 680  * The loglevels go from 0 to 14. Higher numbers imply the most
 681  * verbosity (higher event throughput expected.
 682  *
 683  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 684  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 685  * debug information.
 686  *
 687  * TRACE_EMERG           0
 688  * system is unusable
 689  *
 690  * TRACE_ALERT           1
 691  * action must be taken immediately
 692  *
 693  * TRACE_CRIT            2
 694  * critical conditions
 695  *
 696  * TRACE_ERR             3
 697  * error conditions
 698  *
 699  * TRACE_WARNING         4
 700  * warning conditions
 701  *
 702  * TRACE_NOTICE          5
 703  * normal, but significant, condition
 704  *
 705  * TRACE_INFO            6
 706  * informational message
 707  *
 708  * TRACE_DEBUG_SYSTEM    7
 709  * debug information with system-level scope (set of programs)
 710  *
 711  * TRACE_DEBUG_PROGRAM   8
 712  * debug information with program-level scope (set of processes)
 713  *
 714  * TRACE_DEBUG_PROCESS   9
 715  * debug information with process-level scope (set of modules)
 716  *
 717  * TRACE_DEBUG_MODULE    10
 718  * debug information with module (executable/library) scope (set of units)
 719  *
 720  * TRACE_DEBUG_UNIT      11
 721  * debug information with compilation unit scope (set of functions)
 722  *
 723  * TRACE_DEBUG_FUNCTION  12
 724  * debug information with function-level scope
 725  *
 726  * TRACE_DEBUG_LINE      13
 727  * debug information with line-level scope (TRACEPOINT_EVENT default)
 728  *
 729  * TRACE_DEBUG           14
 730  * debug-level message
 731  *
 732  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 733  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 734  * tracepoint name. The first field is the provider name, the second
 735  * field is the name of the tracepoint, the third field is the loglevel
 736  * name.
 737  *
 738  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 739  *              < loglevel_name >)
 740  *
 741  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 742  * TRACEPOINT_LOGLEVEL.
 743  */
 744
 745 enum {
 746         TRACE_EMERG             = 0,
 747         TRACE_ALERT             = 1,
 748         TRACE_CRIT              = 2,
 749         TRACE_ERR               = 3,
 750         TRACE_WARNING           = 4,
 751         TRACE_NOTICE            = 5,
 752         TRACE_INFO              = 6,
 753         TRACE_DEBUG_SYSTEM      = 7,
 754         TRACE_DEBUG_PROGRAM     = 8,
 755         TRACE_DEBUG_PROCESS     = 9,
 756         TRACE_DEBUG_MODULE      = 10,
 757         TRACE_DEBUG_UNIT        = 11,
 758         TRACE_DEBUG_FUNCTION    = 12,
 759         TRACE_DEBUG_LINE        = 13,
 760         TRACE_DEBUG             = 14,
 761 };
 762
 763 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 764
 765 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 766
 767 #ifndef TRACEPOINT_MODEL_EMF_URI
 768
 769 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 770
 771 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */