include/lttng/tracepoint.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #ifndef _LTTNG_TRACEPOINT_H
   8 #define _LTTNG_TRACEPOINT_H
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <lttng/tracepoint-types.h>
  13 #include <lttng/tracepoint-rcu.h>
  14 #include <urcu/compiler.h>
  15 #include <urcu/system.h>
  16 #include <dlfcn.h>      /* for dlopen */
  17 #include <string.h>     /* for memset */
  18
  19 #include <lttng/ust-config.h>   /* for sdt */
  20 #include <lttng/ust-compiler.h>
  21 #include <lttng/ust-tracer.h>
  22
  23 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  24 /*
  25  * Instead of using SDT_USE_VARIADIC from 'sys/sdt.h', use our own namespaced
  26  * macros since the instrumented application might already have included
  27  * 'sys/sdt.h' without variadic support.
  28  */
  29 #include <sys/sdt.h>
  30
  31 #define _LTTNG_SDT_NARG(...) \
  32         __LTTNG_SDT_NARG(__VA_ARGS__, 12,11,10,9,8,7,6,5,4,3,2,1,0)
  33
  34 #define __LTTNG_SDT_NARG(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12, N, ...) N
  35
  36 #define _LTTNG_SDT_PROBE_N(provider, name, N, ...) \
  37         _SDT_PROBE(provider, name, N, (__VA_ARGS__))
  38
  39 #define LTTNG_STAP_PROBEV(provider, name, ...) \
  40         _LTTNG_SDT_PROBE_N(provider, name, _LTTNG_SDT_NARG(0, ##__VA_ARGS__), ##__VA_ARGS__)
  41
  42 #else
  43 #define LTTNG_STAP_PROBEV(...)
  44 #endif
  45
  46 #ifdef __cplusplus
  47 extern "C" {
  48 #endif
  49
  50 #define tracepoint_enabled(provider, name) \
  51         caa_unlikely(CMM_LOAD_SHARED(__tracepoint_##provider##___##name.state))
  52
  53 #define do_tracepoint(provider, name, ...) \
  54         __tracepoint_cb_##provider##___##name(__VA_ARGS__)
  55
  56 #define tracepoint(provider, name, ...)                                     \
  57         do {                                                                \
  58                 LTTNG_STAP_PROBEV(provider, name, ## __VA_ARGS__);          \
  59                 if (tracepoint_enabled(provider, name))                     \
  60                         do_tracepoint(provider, name, __VA_ARGS__);         \
  61         } while (0)
  62
  63 #define TP_ARGS(...)       __VA_ARGS__
  64
  65 /*
  66  * TP_ARGS takes tuples of type, argument separated by a comma.
  67  * It can take up to 10 tuples (which means that less than 10 tuples is
  68  * fine too).
  69  * Each tuple is also separated by a comma.
  70  */
  71 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  72                 _tokena##_tokenb
  73 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  74                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  75 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  76                 _tokena##_tokenb##_tokenc
  77 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  78                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  79 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  80                 _tokena##_tokenb##_tokenc##_tokend
  81 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  82                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  83
  84 /*
  85  * _TP_EXVAR* extract the var names.
  86  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  87  */
  88 #define _TP_EXVAR0()
  89 #define _TP_EXVAR1(a)
  90 #define _TP_EXVAR2(a,b)                                         b
  91 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  92 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  93 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  94 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  95 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  96 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  97 #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
  98 #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
  99 #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
 100
 101 #define _TP_EXDATA_VAR0()                                               __tp_data
 102 #define _TP_EXDATA_VAR1(a)                                              __tp_data
 103 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
 104 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
 105 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
 106 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
 107 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
 108 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 109 #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
 110 #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
 111 #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
 112 #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
 113
 114 /*
 115  * _TP_EXPROTO* extract tuples of type, var.
 116  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 117  */
 118 #define _TP_EXPROTO0()                                          void
 119 #define _TP_EXPROTO1(a)                                         void
 120 #define _TP_EXPROTO2(a,b)                                       a b
 121 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 122 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 123 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 124 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 125 #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
 126 #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
 127 #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
 128 #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
 129 #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
 130
 131 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 132 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 133 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 134 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 135 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 136 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 137 #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
 138 #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
 139 #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
 140 #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
 141 #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
 142 #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
 143
 144 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 145 #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)
 146 #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
 147 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 148 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 149 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 150 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 151 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 152 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 153 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 154 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 155 #define _TP_PARAMS(...)                 __VA_ARGS__
 156
 157 /*
 158  * The tracepoint cb is marked always inline so we can distinguish
 159  * between caller's ip addresses within the probe using the return
 160  * address.
 161  */
 162 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 163 extern struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name;                \
 164 static inline                                                                           \
 165 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 166         __attribute__((always_inline, unused)) lttng_ust_notrace;                       \
 167 static                                                                                  \
 168 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 169 {                                                                                       \
 170         struct lttng_ust_tracepoint_probe *__tp_probe;                                  \
 171                                                                                         \
 172         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 173                 return;                                                                 \
 174         tp_rcu_read_lock();                                                             \
 175         __tp_probe = tp_rcu_dereference(__tracepoint_##_provider##___##_name.probes);   \
 176         if (caa_unlikely(!__tp_probe))                                                  \
 177                 goto end;                                                               \
 178         do {                                                                            \
 179                 void (*__tp_cb)(void) = __tp_probe->func;                               \
 180                 void *__tp_data = __tp_probe->data;                                     \
 181                                                                                         \
 182                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 183                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 184         } while ((++__tp_probe)->func);                                                 \
 185 end:                                                                                    \
 186         tp_rcu_read_unlock();                                                           \
 187 }                                                                                       \
 188 static inline lttng_ust_notrace                                                         \
 189 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 190                 void (*func)(void), void *data);                                        \
 191 static inline                                                                           \
 192 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 193                 void (*func)(void), void *data)                                         \
 194 {                                                                                       \
 195         __tracepoint_probe_register(name, func, data,                                   \
 196                 __tracepoint_##_provider##___##_name.signature);                        \
 197 }                                                                                       \
 198 static inline lttng_ust_notrace                                                         \
 199 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 200                 void (*func)(void), void *data);                                        \
 201 static inline                                                                           \
 202 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 203                 void (*func)(void), void *data)                                         \
 204 {                                                                                       \
 205         __tracepoint_probe_unregister(name, func, data);                                \
 206 }
 207
 208 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 209                 void *data, const char *signature);
 210 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 211                 void *data);
 212
 213 /*
 214  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 215  * shared across objects in a module/main executable.
 216  *
 217  * IMPORTANT: this structure is part of the ABI between instrumented
 218  * applications and UST. Fields need to be only added at the end, never
 219  * reordered, never removed.
 220  *
 221  * The field @struct_size should be used to determine the size of the
 222  * structure. It should be queried before using additional fields added
 223  * at the end of the structure.
 224  */
 225 struct lttng_ust_tracepoint_dlopen {
 226         uint32_t struct_size;
 227
 228         void *liblttngust_handle;
 229
 230         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 231                 int tracepoints_count);
 232         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 233         void (*rcu_read_lock_sym)(void);
 234         void (*rcu_read_unlock_sym)(void);
 235         void *(*rcu_dereference_sym)(void *p);
 236
 237         /* End of base ABI. Fields below should be used after checking struct_size. */
 238 };
 239
 240 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 241 extern struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr;
 242
 243 /*
 244  * These weak symbols, the constructor, and destructor take care of
 245  * registering only _one_ instance of the tracepoints per shared-ojbect
 246  * (or for the whole main program).
 247  */
 248 int __tracepoint_registered
 249         __attribute__((weak, visibility("hidden")));
 250 int __tracepoint_ptrs_registered
 251         __attribute__((weak, visibility("hidden")));
 252 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 253                 __attribute__((weak, visibility("hidden"))) = {
 254         .struct_size = sizeof(struct lttng_ust_tracepoint_dlopen),
 255 };
 256 /*
 257  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 258  * 4.8 and prior does not have the same behavior for symbol scoping on
 259  * 32-bit powerpc depending on the object size: symbols for objects of 8
 260  * bytes or less have the same address throughout a module, whereas they
 261  * have different addresses between compile units for objects larger
 262  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 263  * scoping match that of the other weak hidden symbols found in this
 264  * header.
 265  */
 266 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 267         __attribute__((weak, visibility("hidden")));
 268
 269 /*
 270  * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared
 271  * across objects in a module/main executable. The callbacks are used to
 272  * control and check if the destructors should be executed.
 273  *
 274  * IMPORTANT: this structure is part of the ABI between instrumented
 275  * applications and UST. Fields need to be only added at the end, never
 276  * reordered, never removed.
 277  *
 278  * The field @struct_size should be used to determine the size of the
 279  * structure. It should be queried before using additional fields added
 280  * at the end of the structure.
 281  */
 282 struct lttng_ust_tracepoint_destructors_syms {
 283         uint32_t struct_size;
 284
 285         void (*tracepoint_disable_destructors)(void);
 286         int (*tracepoint_get_destructors_state)(void);
 287
 288         /* End of base ABI. Fields below should be used after checking struct_size. */
 289 };
 290
 291 extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms;
 292 extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr;
 293
 294 struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms
 295         __attribute__((weak, visibility("hidden"))) = {
 296         .struct_size = sizeof(struct lttng_ust_tracepoint_destructors_syms),
 297 };
 298 struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr
 299         __attribute__((weak, visibility("hidden")));
 300
 301 static inline void tracepoint_disable_destructors(void)
 302 {
 303         if (!tracepoint_dlopen_ptr)
 304                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 305         if (!tracepoint_destructors_syms_ptr)
 306                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 307         if (tracepoint_dlopen_ptr->liblttngust_handle
 308                         && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors)
 309                 tracepoint_destructors_syms_ptr->tracepoint_disable_destructors();
 310 }
 311
 312 #ifndef _LGPL_SOURCE
 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         if (!tracepoint_dlopen_ptr)
 319                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 320         /*
 321          * Symbols below are needed by tracepoint call sites and probe
 322          * providers.
 323          */
 324         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym)
 325                 tracepoint_dlopen_ptr->rcu_read_lock_sym =
 326                         URCU_FORCE_CAST(void (*)(void),
 327                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 328                                         "tp_rcu_read_lock"));
 329         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym)
 330                 tracepoint_dlopen_ptr->rcu_read_unlock_sym =
 331                         URCU_FORCE_CAST(void (*)(void),
 332                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 333                                         "tp_rcu_read_unlock"));
 334         if (!tracepoint_dlopen_ptr->rcu_dereference_sym)
 335                 tracepoint_dlopen_ptr->rcu_dereference_sym =
 336                         URCU_FORCE_CAST(void *(*)(void *p),
 337                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 338                                         "tp_rcu_dereference_sym"));
 339 }
 340 #else
 341 static inline void lttng_ust_notrace
 342 __tracepoint__init_urcu_sym(void);
 343 static inline void
 344 __tracepoint__init_urcu_sym(void)
 345 {
 346 }
 347 #endif
 348
 349 static void lttng_ust_notrace __attribute__((constructor))
 350 __tracepoints__init(void);
 351 static void
 352 __tracepoints__init(void)
 353 {
 354         if (__tracepoint_registered++) {
 355                 if (!tracepoint_dlopen_ptr->liblttngust_handle)
 356                         return;
 357                 __tracepoint__init_urcu_sym();
 358                 return;
 359         }
 360
 361         if (!tracepoint_dlopen_ptr)
 362                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 363         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 364                 tracepoint_dlopen_ptr->liblttngust_handle =
 365                         dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
 366         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 367                 return;
 368         __tracepoint__init_urcu_sym();
 369 }
 370
 371 static void lttng_ust_notrace __attribute__((destructor))
 372 __tracepoints__destroy(void);
 373 static void
 374 __tracepoints__destroy(void)
 375 {
 376         int ret;
 377
 378         if (--__tracepoint_registered)
 379                 return;
 380         if (!tracepoint_dlopen_ptr)
 381                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 382         if (!tracepoint_destructors_syms_ptr)
 383                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 384         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 385                 return;
 386         if (__tracepoint_ptrs_registered)
 387                 return;
 388         /*
 389          * Lookup if destructors must be executed using the new method.
 390          */
 391         if (tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 392                 && !tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()) {
 393                 /*
 394                  * The tracepoint_get_destructors_state symbol was found with
 395                  * dlsym but its returned value is 0 meaning that destructors
 396                  * must not be executed.
 397                  */
 398                 return;
 399         }
 400         ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 401         if (ret) {
 402                 fprintf(stderr, "Error (%d) in dlclose\n", ret);
 403                 abort();
 404         }
 405         memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 406 }
 407
 408 #ifdef TRACEPOINT_DEFINE
 409
 410 /*
 411  * These weak symbols, the constructor, and destructor take care of
 412  * registering only _one_ instance of the tracepoints per shared-ojbect
 413  * (or for the whole main program).
 414  */
 415 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 416         __attribute__((weak, visibility("hidden")));
 417 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 418         __attribute__((weak, visibility("hidden")));
 419
 420 /*
 421  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 422  * unresolved symbol that requires the provider to be linked in. When
 423  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 424  * unresolved symbol that depends on having the provider linked in,
 425  * otherwise the linker complains. This deals with use of static
 426  * libraries, ensuring that the linker does not remove the provider
 427  * object from the executable.
 428  */
 429 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 430 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 431 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 432 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 433 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 434
 435 /*
 436  * Note: to allow PIC code, we need to allow the linker to update the pointers
 437  * in the __tracepoints_ptrs section.
 438  * Therefore, this section is _not_ const (read-only).
 439  */
 440 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 441
 442 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 443         extern int __tracepoint_provider_##_provider;                           \
 444         static const char __tp_strtab_##_provider##___##_name[]                 \
 445                 __attribute__((section("__tracepoints_strings"))) =             \
 446                         #_provider ":" #_name;                                  \
 447         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 448                 __attribute__((section("__tracepoints"))) = {                   \
 449                         sizeof(struct lttng_ust_tracepoint),                    \
 450                         __tp_strtab_##_provider##___##_name,                    \
 451                         0,                                                      \
 452                         NULL,                                                   \
 453                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 454                         _TP_EXTRACT_STRING(_args),                              \
 455                 };                                                              \
 456         static struct lttng_ust_tracepoint *                                    \
 457                 __tracepoint_ptr_##_provider##___##_name                        \
 458                 __attribute__((section("__tracepoints_ptrs"), used))            \
 459                 __lttng_ust_variable_attribute_no_sanitize_address =            \
 460                         &__tracepoint_##_provider##___##_name;
 461
 462 static void lttng_ust_notrace __attribute__((constructor))
 463 __tracepoints__ptrs_init(void);
 464 static void
 465 __tracepoints__ptrs_init(void)
 466 {
 467         if (__tracepoint_ptrs_registered++)
 468                 return;
 469         if (!tracepoint_dlopen_ptr)
 470                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 471         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 472                 tracepoint_dlopen_ptr->liblttngust_handle =
 473                         dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
 474         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 475                 return;
 476         if (!tracepoint_destructors_syms_ptr)
 477                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 478         tracepoint_dlopen_ptr->tracepoint_register_lib =
 479                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 480                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 481                                         "tracepoint_register_lib"));
 482         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 483                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 484                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 485                                         "tracepoint_unregister_lib"));
 486         tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
 487                 URCU_FORCE_CAST(void (*)(void),
 488                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 489                                         "tp_disable_destructors"));
 490         tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state =
 491                 URCU_FORCE_CAST(int (*)(void),
 492                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 493                                         "tp_get_destructors_state"));
 494         __tracepoint__init_urcu_sym();
 495         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 496                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 497                                 __stop___tracepoints_ptrs -
 498                                 __start___tracepoints_ptrs);
 499         }
 500 }
 501
 502 static void lttng_ust_notrace __attribute__((destructor))
 503 __tracepoints__ptrs_destroy(void);
 504 static void
 505 __tracepoints__ptrs_destroy(void)
 506 {
 507         int ret;
 508
 509         if (--__tracepoint_ptrs_registered)
 510                 return;
 511         if (!tracepoint_dlopen_ptr)
 512                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 513         if (!tracepoint_destructors_syms_ptr)
 514                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 515         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 516                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 517         if (tracepoint_dlopen_ptr->liblttngust_handle
 518                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 519                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
 520                         && !__tracepoint_ptrs_registered) {
 521                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 522                 if (ret) {
 523                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 524                         abort();
 525                 }
 526                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 527         }
 528 }
 529
 530 #else /* TRACEPOINT_DEFINE */
 531
 532 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 533
 534 #endif /* #else TRACEPOINT_DEFINE */
 535
 536 #ifdef __cplusplus
 537 }
 538 #endif
 539
 540 #endif /* _LTTNG_TRACEPOINT_H */
 541
 542 /* The following declarations must be outside re-inclusion protection. */
 543
 544 #ifndef TRACEPOINT_ENUM
 545
 546 /*
 547  * Tracepoint Enumerations
 548  *
 549  * The enumeration is a mapping between an integer, or range of integers, and
 550  * a string. It can be used to have a more compact trace in cases where the
 551  * possible values for a field are limited:
 552  *
 553  * An example:
 554  *
 555  * TRACEPOINT_ENUM(someproject_component, enumname,
 556  *      TP_ENUM_VALUES(
 557  *              ctf_enum_value("even", 0)
 558  *              ctf_enum_value("uneven", 1)
 559  *              ctf_enum_range("twoto4", 2, 4)
 560  *              ctf_enum_value("five", 5)
 561  *      )
 562  * )
 563  *
 564  * Where "someproject_component" is the name of the component this enumeration
 565  * belongs to and "enumname" identifies this enumeration. Inside the
 566  * TP_ENUM_VALUES macro is the actual mapping. Each string value can map
 567  * to either a single value with ctf_enum_value or a range of values
 568  * with ctf_enum_range.
 569  *
 570  * Enumeration ranges may overlap, but the behavior is implementation-defined,
 571  * each trace reader will handle overlapping as it wishes.
 572  *
 573  * That enumeration can then be used in a field inside the TP_FIELD macro using
 574  * the following line:
 575  *
 576  * ctf_enum(someproject_component, enumname, enumtype, enumfield, enumval)
 577  *
 578  * Where "someproject_component" and "enumname" match those in the
 579  * TRACEPOINT_ENUM, "enumtype" is a signed or unsigned integer type
 580  * backing the enumeration, "enumfield" is the name of the field and
 581  * "enumval" is the value.
 582  */
 583
 584 #define TRACEPOINT_ENUM(provider, name, values)
 585
 586 #endif /* #ifndef TRACEPOINT_ENUM */
 587
 588 #ifndef TRACEPOINT_EVENT
 589
 590 /*
 591  * How to use the TRACEPOINT_EVENT macro:
 592  *
 593  * An example:
 594  *
 595  * TRACEPOINT_EVENT(someproject_component, event_name,
 596  *
 597  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 598  *
 599  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 600  *             long *, arg4, size_t, arg4_len),
 601  *
 602  *      * TP_FIELDS describes the event payload layout in the trace *
 603  *
 604  *     TP_FIELDS(
 605  *         * Integer, printed in base 10 *
 606  *         ctf_integer(int, field_a, arg0)
 607  *
 608  *         * Integer, printed with 0x base 16 *
 609  *         ctf_integer_hex(unsigned long, field_d, arg1)
 610  *
 611  *         * Enumeration *
 612  *         ctf_enum(someproject_component, enum_name, int, field_e, arg0)
 613  *
 614  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 615  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 616  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 617  *
 618  *         * String, printed as UTF8-encoded string *
 619  *         ctf_string(field_e, string)
 620  *
 621  *         * Array sequence of signed integer values *
 622  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 623  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 624  *     )
 625  * )
 626  *
 627  * More detailed explanation:
 628  *
 629  * The name of the tracepoint is expressed as a tuple with the provider
 630  * and name arguments.
 631  *
 632  * The provider and name should be a proper C99 identifier.
 633  * The "provider" and "name" MUST follow these rules to ensure no
 634  * namespace clash occurs:
 635  *
 636  * For projects (applications and libraries) for which an entity
 637  * specific to the project controls the source code and thus its
 638  * tracepoints (typically with a scope larger than a single company):
 639  *
 640  * either:
 641  *   project_component, event
 642  * or:
 643  *   project, event
 644  *
 645  * Where "project" is the name of the project,
 646  *       "component" is the name of the project component (which may
 647  *       include several levels of sub-components, e.g.
 648  *       ...component_subcomponent_...) where the tracepoint is located
 649  *       (optional),
 650  *       "event" is the name of the tracepoint event.
 651  *
 652  * For projects issued from a single company wishing to advertise that
 653  * the company controls the source code and thus the tracepoints, the
 654  * "com_" prefix should be used:
 655  *
 656  * either:
 657  *   com_company_project_component, event
 658  * or:
 659  *   com_company_project, event
 660  *
 661  * Where "company" is the name of the company,
 662  *       "project" is the name of the project,
 663  *       "component" is the name of the project component (which may
 664  *       include several levels of sub-components, e.g.
 665  *       ...component_subcomponent_...) where the tracepoint is located
 666  *       (optional),
 667  *       "event" is the name of the tracepoint event.
 668  *
 669  * the provider:event identifier is limited to 127 characters.
 670  */
 671
 672 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 673         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 674         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 675
 676 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 677
 678 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 679         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 680         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 681
 682 #endif /* #ifndef TRACEPOINT_EVENT */
 683
 684 #ifndef TRACEPOINT_LOGLEVEL
 685
 686 /*
 687  * Tracepoint Loglevels
 688  *
 689  * Typical use of these loglevels:
 690  *
 691  * The loglevels go from 0 to 14. Higher numbers imply the most
 692  * verbosity (higher event throughput expected.
 693  *
 694  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 695  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 696  * debug information.
 697  *
 698  * TRACE_EMERG           0
 699  * system is unusable
 700  *
 701  * TRACE_ALERT           1
 702  * action must be taken immediately
 703  *
 704  * TRACE_CRIT            2
 705  * critical conditions
 706  *
 707  * TRACE_ERR             3
 708  * error conditions
 709  *
 710  * TRACE_WARNING         4
 711  * warning conditions
 712  *
 713  * TRACE_NOTICE          5
 714  * normal, but significant, condition
 715  *
 716  * TRACE_INFO            6
 717  * informational message
 718  *
 719  * TRACE_DEBUG_SYSTEM    7
 720  * debug information with system-level scope (set of programs)
 721  *
 722  * TRACE_DEBUG_PROGRAM   8
 723  * debug information with program-level scope (set of processes)
 724  *
 725  * TRACE_DEBUG_PROCESS   9
 726  * debug information with process-level scope (set of modules)
 727  *
 728  * TRACE_DEBUG_MODULE    10
 729  * debug information with module (executable/library) scope (set of units)
 730  *
 731  * TRACE_DEBUG_UNIT      11
 732  * debug information with compilation unit scope (set of functions)
 733  *
 734  * TRACE_DEBUG_FUNCTION  12
 735  * debug information with function-level scope
 736  *
 737  * TRACE_DEBUG_LINE      13
 738  * debug information with line-level scope (TRACEPOINT_EVENT default)
 739  *
 740  * TRACE_DEBUG           14
 741  * debug-level message
 742  *
 743  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 744  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 745  * tracepoint name. The first field is the provider name, the second
 746  * field is the name of the tracepoint, the third field is the loglevel
 747  * name.
 748  *
 749  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 750  *              < loglevel_name >)
 751  *
 752  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 753  * TRACEPOINT_LOGLEVEL.
 754  */
 755
 756 enum {
 757         TRACE_EMERG             = 0,
 758         TRACE_ALERT             = 1,
 759         TRACE_CRIT              = 2,
 760         TRACE_ERR               = 3,
 761         TRACE_WARNING           = 4,
 762         TRACE_NOTICE            = 5,
 763         TRACE_INFO              = 6,
 764         TRACE_DEBUG_SYSTEM      = 7,
 765         TRACE_DEBUG_PROGRAM     = 8,
 766         TRACE_DEBUG_PROCESS     = 9,
 767         TRACE_DEBUG_MODULE      = 10,
 768         TRACE_DEBUG_UNIT        = 11,
 769         TRACE_DEBUG_FUNCTION    = 12,
 770         TRACE_DEBUG_LINE        = 13,
 771         TRACE_DEBUG             = 14,
 772 };
 773
 774 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 775
 776 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 777
 778 #ifndef TRACEPOINT_MODEL_EMF_URI
 779
 780 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 781
 782 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */