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 #include <lttng/ust-config.h>   /* for sdt */
  19 #include <lttng/ust-compiler.h>
  20
  21 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  22 /*
  23  * Instead of using SDT_USE_VARIADIC from 'sys/sdt.h', use our own namespaced
  24  * macros since the instrumented application might already have included
  25  * 'sys/sdt.h' without variadic support.
  26  */
  27 #include <sys/sdt.h>
  28
  29 #define _LTTNG_SDT_NARG(...) \
  30         __LTTNG_SDT_NARG(__VA_ARGS__, 12,11,10,9,8,7,6,5,4,3,2,1,0)
  31
  32 #define __LTTNG_SDT_NARG(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12, N, ...) N
  33
  34 #define _LTTNG_SDT_PROBE_N(provider, name, N, ...) \
  35         _SDT_PROBE(provider, name, N, (__VA_ARGS__))
  36
  37 #define LTTNG_STAP_PROBEV(provider, name, ...) \
  38         _LTTNG_SDT_PROBE_N(provider, name, _LTTNG_SDT_NARG(0, ##__VA_ARGS__), ##__VA_ARGS__)
  39
  40 #else
  41 #define LTTNG_STAP_PROBEV(...)
  42 #endif
  43
  44 #ifdef __cplusplus
  45 extern "C" {
  46 #endif
  47
  48 #define tracepoint_enabled(provider, name) \
  49         caa_unlikely(CMM_LOAD_SHARED(__tracepoint_##provider##___##name.state))
  50
  51 #define do_tracepoint(provider, name, ...) \
  52         __tracepoint_cb_##provider##___##name(__VA_ARGS__)
  53
  54 #define tracepoint(provider, name, ...)                                     \
  55         do {                                                                \
  56                 LTTNG_STAP_PROBEV(provider, name, ## __VA_ARGS__);          \
  57                 if (tracepoint_enabled(provider, name))                     \
  58                         do_tracepoint(provider, name, __VA_ARGS__);         \
  59         } while (0)
  60
  61 #define TP_ARGS(...)       __VA_ARGS__
  62
  63 /*
  64  * TP_ARGS takes tuples of type, argument separated by a comma.
  65  * It can take up to 10 tuples (which means that less than 10 tuples is
  66  * fine too).
  67  * Each tuple is also separated by a comma.
  68  */
  69 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  70                 _tokena##_tokenb
  71 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  72                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  73 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  74                 _tokena##_tokenb##_tokenc
  75 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  76                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  77 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  78                 _tokena##_tokenb##_tokenc##_tokend
  79 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  80                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  81
  82 /*
  83  * _TP_EXVAR* extract the var names.
  84  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  85  */
  86 #define _TP_EXVAR0()
  87 #define _TP_EXVAR1(a)
  88 #define _TP_EXVAR2(a,b)                                         b
  89 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  90 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  91 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  92 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  93 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  94 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  95 #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
  96 #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
  97 #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
  98
  99 #define _TP_EXDATA_VAR0()                                               __tp_data
 100 #define _TP_EXDATA_VAR1(a)                                              __tp_data
 101 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
 102 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
 103 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
 104 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
 105 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
 106 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 107 #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
 108 #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
 109 #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
 110 #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
 111
 112 /*
 113  * _TP_EXPROTO* extract tuples of type, var.
 114  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 115  */
 116 #define _TP_EXPROTO0()                                          void
 117 #define _TP_EXPROTO1(a)                                         void
 118 #define _TP_EXPROTO2(a,b)                                       a b
 119 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 120 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 121 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 122 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 123 #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
 124 #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
 125 #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
 126 #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
 127 #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
 128
 129 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 130 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 131 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 132 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 133 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 134 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 135 #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
 136 #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
 137 #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
 138 #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
 139 #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
 140 #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
 141
 142 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 143 #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)
 144 #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
 145 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 146 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 147 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 148 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 149 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 150 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 151 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 152 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 153 #define _TP_PARAMS(...)                 __VA_ARGS__
 154
 155 /*
 156  * The tracepoint cb is marked always inline so we can distinguish
 157  * between caller's ip addresses within the probe using the return
 158  * address.
 159  */
 160 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 161 extern struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name;                \
 162 static inline __attribute__((always_inline, unused)) lttng_ust_notrace                  \
 163 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__));              \
 164 static                                                                                  \
 165 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 166 {                                                                                       \
 167         struct lttng_ust_tracepoint_probe *__tp_probe;                                  \
 168                                                                                         \
 169         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 170                 return;                                                                 \
 171         tp_rcu_read_lock();                                                             \
 172         __tp_probe = tp_rcu_dereference(__tracepoint_##_provider##___##_name.probes);   \
 173         if (caa_unlikely(!__tp_probe))                                                  \
 174                 goto end;                                                               \
 175         do {                                                                            \
 176                 void (*__tp_cb)(void) = __tp_probe->func;                               \
 177                 void *__tp_data = __tp_probe->data;                                     \
 178                                                                                         \
 179                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 180                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 181         } while ((++__tp_probe)->func);                                                 \
 182 end:                                                                                    \
 183         tp_rcu_read_unlock();                                                           \
 184 }                                                                                       \
 185 static inline lttng_ust_notrace                                                         \
 186 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 187                 void (*func)(void), void *data);                                        \
 188 static inline                                                                           \
 189 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 190                 void (*func)(void), void *data)                                         \
 191 {                                                                                       \
 192         __tracepoint_probe_register(name, func, data,                                   \
 193                 __tracepoint_##_provider##___##_name.signature);                        \
 194 }                                                                                       \
 195 static inline lttng_ust_notrace                                                         \
 196 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 197                 void (*func)(void), void *data);                                        \
 198 static inline                                                                           \
 199 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 200                 void (*func)(void), void *data)                                         \
 201 {                                                                                       \
 202         __tracepoint_probe_unregister(name, func, data);                                \
 203 }
 204
 205 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 206                 void *data, const char *signature);
 207 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 208                 void *data);
 209
 210 /*
 211  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 212  * shared across objects in a module/main executable.
 213  *
 214  * IMPORTANT: this structure is part of the ABI between instrumented
 215  * applications and UST. Fields need to be only added at the end, never
 216  * reordered, never removed.
 217  *
 218  * The field @struct_size should be used to determine the size of the
 219  * structure. It should be queried before using additional fields added
 220  * at the end of the structure.
 221  */
 222 struct lttng_ust_tracepoint_dlopen {
 223         uint32_t struct_size;
 224
 225         void *liblttngust_handle;
 226
 227         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 228                 int tracepoints_count);
 229         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 230         void (*rcu_read_lock_sym)(void);
 231         void (*rcu_read_unlock_sym)(void);
 232         void *(*rcu_dereference_sym)(void *p);
 233
 234         /* End of base ABI. Fields below should be used after checking struct_size. */
 235 };
 236
 237 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 238 extern struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr;
 239
 240 /*
 241  * These weak symbols, the constructor, and destructor take care of
 242  * registering only _one_ instance of the tracepoints per shared-ojbect
 243  * (or for the whole main program).
 244  */
 245 int __tracepoint_registered
 246         __attribute__((weak, visibility("hidden")));
 247 int __tracepoint_ptrs_registered
 248         __attribute__((weak, visibility("hidden")));
 249 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 250                 __attribute__((weak, visibility("hidden"))) = {
 251         .struct_size = sizeof(struct lttng_ust_tracepoint_dlopen),
 252 };
 253 /*
 254  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 255  * 4.8 and prior does not have the same behavior for symbol scoping on
 256  * 32-bit powerpc depending on the object size: symbols for objects of 8
 257  * bytes or less have the same address throughout a module, whereas they
 258  * have different addresses between compile units for objects larger
 259  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 260  * scoping match that of the other weak hidden symbols found in this
 261  * header.
 262  */
 263 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 264         __attribute__((weak, visibility("hidden")));
 265
 266 /*
 267  * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared
 268  * across objects in a module/main executable. The callbacks are used to
 269  * control and check if the destructors should be executed.
 270  *
 271  * IMPORTANT: this structure is part of the ABI between instrumented
 272  * applications and UST. Fields need to be only added at the end, never
 273  * reordered, never removed.
 274  *
 275  * The field @struct_size should be used to determine the size of the
 276  * structure. It should be queried before using additional fields added
 277  * at the end of the structure.
 278  */
 279 struct lttng_ust_tracepoint_destructors_syms {
 280         uint32_t struct_size;
 281
 282         void (*tracepoint_disable_destructors)(void);
 283         int (*tracepoint_get_destructors_state)(void);
 284
 285         /* End of base ABI. Fields below should be used after checking struct_size. */
 286 };
 287
 288 extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms;
 289 extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr;
 290
 291 struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms
 292         __attribute__((weak, visibility("hidden"))) = {
 293         .struct_size = sizeof(struct lttng_ust_tracepoint_destructors_syms),
 294 };
 295 struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr
 296         __attribute__((weak, visibility("hidden")));
 297
 298 static inline void tracepoint_disable_destructors(void)
 299 {
 300         if (!tracepoint_dlopen_ptr)
 301                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 302         if (!tracepoint_destructors_syms_ptr)
 303                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 304         if (tracepoint_dlopen_ptr->liblttngust_handle
 305                         && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors)
 306                 tracepoint_destructors_syms_ptr->tracepoint_disable_destructors();
 307 }
 308
 309 #ifndef _LGPL_SOURCE
 310 static inline void lttng_ust_notrace
 311 __tracepoint__init_urcu_sym(void);
 312 static inline void
 313 __tracepoint__init_urcu_sym(void)
 314 {
 315         if (!tracepoint_dlopen_ptr)
 316                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 317         /*
 318          * Symbols below are needed by tracepoint call sites and probe
 319          * providers.
 320          */
 321         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym)
 322                 tracepoint_dlopen_ptr->rcu_read_lock_sym =
 323                         URCU_FORCE_CAST(void (*)(void),
 324                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 325                                         "tp_rcu_read_lock"));
 326         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym)
 327                 tracepoint_dlopen_ptr->rcu_read_unlock_sym =
 328                         URCU_FORCE_CAST(void (*)(void),
 329                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 330                                         "tp_rcu_read_unlock"));
 331         if (!tracepoint_dlopen_ptr->rcu_dereference_sym)
 332                 tracepoint_dlopen_ptr->rcu_dereference_sym =
 333                         URCU_FORCE_CAST(void *(*)(void *p),
 334                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 335                                         "tp_rcu_dereference_sym"));
 336 }
 337 #else
 338 static inline void lttng_ust_notrace
 339 __tracepoint__init_urcu_sym(void);
 340 static inline void
 341 __tracepoint__init_urcu_sym(void)
 342 {
 343 }
 344 #endif
 345
 346 static void lttng_ust_notrace __attribute__((constructor))
 347 __tracepoints__init(void);
 348 static void
 349 __tracepoints__init(void)
 350 {
 351         if (__tracepoint_registered++) {
 352                 if (!tracepoint_dlopen_ptr->liblttngust_handle)
 353                         return;
 354                 __tracepoint__init_urcu_sym();
 355                 return;
 356         }
 357
 358         if (!tracepoint_dlopen_ptr)
 359                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 360         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 361                 tracepoint_dlopen_ptr->liblttngust_handle =
 362                         dlopen("liblttng-ust-tracepoint.so.1", RTLD_NOW | RTLD_GLOBAL);
 363         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 364                 return;
 365         __tracepoint__init_urcu_sym();
 366 }
 367
 368 static void lttng_ust_notrace __attribute__((destructor))
 369 __tracepoints__destroy(void);
 370 static void
 371 __tracepoints__destroy(void)
 372 {
 373         int ret;
 374
 375         if (--__tracepoint_registered)
 376                 return;
 377         if (!tracepoint_dlopen_ptr)
 378                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 379         if (!tracepoint_destructors_syms_ptr)
 380                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 381         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 382                 return;
 383         if (__tracepoint_ptrs_registered)
 384                 return;
 385         /*
 386          * Lookup if destructors must be executed using the new method.
 387          */
 388         if (tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 389                 && !tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()) {
 390                 /*
 391                  * The tracepoint_get_destructors_state symbol was found with
 392                  * dlsym but its returned value is 0 meaning that destructors
 393                  * must not be executed.
 394                  */
 395                 return;
 396         }
 397         ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 398         if (ret) {
 399                 fprintf(stderr, "Error (%d) in dlclose\n", ret);
 400                 abort();
 401         }
 402         memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 403 }
 404
 405 #ifdef TRACEPOINT_DEFINE
 406
 407 /*
 408  * These weak symbols, the constructor, and destructor take care of
 409  * registering only _one_ instance of the tracepoints per shared-ojbect
 410  * (or for the whole main program).
 411  */
 412 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 413         __attribute__((weak, visibility("hidden")));
 414 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 415         __attribute__((weak, visibility("hidden")));
 416
 417 /*
 418  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 419  * unresolved symbol that requires the provider to be linked in. When
 420  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 421  * unresolved symbol that depends on having the provider linked in,
 422  * otherwise the linker complains. This deals with use of static
 423  * libraries, ensuring that the linker does not remove the provider
 424  * object from the executable.
 425  */
 426 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 427 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 428 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 429 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 430 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 431
 432 /*
 433  * Note: to allow PIC code, we need to allow the linker to update the pointers
 434  * in the __tracepoints_ptrs section.
 435  * Therefore, this section is _not_ const (read-only).
 436  */
 437 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 438
 439 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 440         extern int __tracepoint_provider_##_provider;                           \
 441         static const char __tp_strtab_##_provider##___##_name[]                 \
 442                 __attribute__((section("__tracepoints_strings"))) =             \
 443                         #_provider ":" #_name;                                  \
 444         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 445                 __attribute__((section("__tracepoints"))) = {                   \
 446                         sizeof(struct lttng_ust_tracepoint),                    \
 447                         __tp_strtab_##_provider##___##_name,                    \
 448                         0,                                                      \
 449                         NULL,                                                   \
 450                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 451                         _TP_EXTRACT_STRING(_args),                              \
 452                 };                                                              \
 453         static struct lttng_ust_tracepoint *                                    \
 454                 __tracepoint_ptr_##_provider##___##_name                        \
 455                 __attribute__((section("__tracepoints_ptrs"), used))            \
 456                 __lttng_ust_variable_attribute_no_sanitize_address =            \
 457                         &__tracepoint_##_provider##___##_name;
 458
 459 static void lttng_ust_notrace __attribute__((constructor))
 460 __tracepoints__ptrs_init(void);
 461 static void
 462 __tracepoints__ptrs_init(void)
 463 {
 464         if (__tracepoint_ptrs_registered++)
 465                 return;
 466         if (!tracepoint_dlopen_ptr)
 467                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 468         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 469                 tracepoint_dlopen_ptr->liblttngust_handle =
 470                         dlopen("liblttng-ust-tracepoint.so.1", RTLD_NOW | RTLD_GLOBAL);
 471         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 472                 return;
 473         if (!tracepoint_destructors_syms_ptr)
 474                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 475         tracepoint_dlopen_ptr->tracepoint_register_lib =
 476                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 477                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 478                                         "tracepoint_register_lib"));
 479         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 480                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 481                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 482                                         "tracepoint_unregister_lib"));
 483         tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
 484                 URCU_FORCE_CAST(void (*)(void),
 485                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 486                                         "tp_disable_destructors"));
 487         tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state =
 488                 URCU_FORCE_CAST(int (*)(void),
 489                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 490                                         "tp_get_destructors_state"));
 491         __tracepoint__init_urcu_sym();
 492         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 493                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 494                                 __stop___tracepoints_ptrs -
 495                                 __start___tracepoints_ptrs);
 496         }
 497 }
 498
 499 static void lttng_ust_notrace __attribute__((destructor))
 500 __tracepoints__ptrs_destroy(void);
 501 static void
 502 __tracepoints__ptrs_destroy(void)
 503 {
 504         int ret;
 505
 506         if (--__tracepoint_ptrs_registered)
 507                 return;
 508         if (!tracepoint_dlopen_ptr)
 509                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 510         if (!tracepoint_destructors_syms_ptr)
 511                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 512         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 513                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 514         if (tracepoint_dlopen_ptr->liblttngust_handle
 515                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 516                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
 517                         && !__tracepoint_ptrs_registered) {
 518                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 519                 if (ret) {
 520                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 521                         abort();
 522                 }
 523                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 524         }
 525 }
 526
 527 #else /* TRACEPOINT_DEFINE */
 528
 529 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 530
 531 #endif /* #else TRACEPOINT_DEFINE */
 532
 533 #ifdef __cplusplus
 534 }
 535 #endif
 536
 537 #endif /* _LTTNG_TRACEPOINT_H */
 538
 539 /* The following declarations must be outside re-inclusion protection. */
 540
 541 #ifndef TRACEPOINT_ENUM
 542
 543 /*
 544  * Tracepoint Enumerations
 545  *
 546  * The enumeration is a mapping between an integer, or range of integers, and
 547  * a string. It can be used to have a more compact trace in cases where the
 548  * possible values for a field are limited:
 549  *
 550  * An example:
 551  *
 552  * TRACEPOINT_ENUM(someproject_component, enumname,
 553  *      TP_ENUM_VALUES(
 554  *              ctf_enum_value("even", 0)
 555  *              ctf_enum_value("uneven", 1)
 556  *              ctf_enum_range("twoto4", 2, 4)
 557  *              ctf_enum_value("five", 5)
 558  *      )
 559  * )
 560  *
 561  * Where "someproject_component" is the name of the component this enumeration
 562  * belongs to and "enumname" identifies this enumeration. Inside the
 563  * TP_ENUM_VALUES macro is the actual mapping. Each string value can map
 564  * to either a single value with ctf_enum_value or a range of values
 565  * with ctf_enum_range.
 566  *
 567  * Enumeration ranges may overlap, but the behavior is implementation-defined,
 568  * each trace reader will handle overlapping as it wishes.
 569  *
 570  * That enumeration can then be used in a field inside the TP_FIELD macro using
 571  * the following line:
 572  *
 573  * ctf_enum(someproject_component, enumname, enumtype, enumfield, enumval)
 574  *
 575  * Where "someproject_component" and "enumname" match those in the
 576  * TRACEPOINT_ENUM, "enumtype" is a signed or unsigned integer type
 577  * backing the enumeration, "enumfield" is the name of the field and
 578  * "enumval" is the value.
 579  */
 580
 581 #define TRACEPOINT_ENUM(provider, name, values)
 582
 583 #endif /* #ifndef TRACEPOINT_ENUM */
 584
 585 #ifndef TRACEPOINT_EVENT
 586
 587 /*
 588  * How to use the TRACEPOINT_EVENT macro:
 589  *
 590  * An example:
 591  *
 592  * TRACEPOINT_EVENT(someproject_component, event_name,
 593  *
 594  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 595  *
 596  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 597  *             long *, arg4, size_t, arg4_len),
 598  *
 599  *      * TP_FIELDS describes the event payload layout in the trace *
 600  *
 601  *     TP_FIELDS(
 602  *         * Integer, printed in base 10 *
 603  *         ctf_integer(int, field_a, arg0)
 604  *
 605  *         * Integer, printed with 0x base 16 *
 606  *         ctf_integer_hex(unsigned long, field_d, arg1)
 607  *
 608  *         * Enumeration *
 609  *         ctf_enum(someproject_component, enum_name, int, field_e, arg0)
 610  *
 611  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 612  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 613  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 614  *
 615  *         * String, printed as UTF8-encoded string *
 616  *         ctf_string(field_e, string)
 617  *
 618  *         * Array sequence of signed integer values *
 619  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 620  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 621  *     )
 622  * )
 623  *
 624  * More detailed explanation:
 625  *
 626  * The name of the tracepoint is expressed as a tuple with the provider
 627  * and name arguments.
 628  *
 629  * The provider and name should be a proper C99 identifier.
 630  * The "provider" and "name" MUST follow these rules to ensure no
 631  * namespace clash occurs:
 632  *
 633  * For projects (applications and libraries) for which an entity
 634  * specific to the project controls the source code and thus its
 635  * tracepoints (typically with a scope larger than a single company):
 636  *
 637  * either:
 638  *   project_component, event
 639  * or:
 640  *   project, event
 641  *
 642  * Where "project" is the name of the project,
 643  *       "component" is the name of the project component (which may
 644  *       include several levels of sub-components, e.g.
 645  *       ...component_subcomponent_...) where the tracepoint is located
 646  *       (optional),
 647  *       "event" is the name of the tracepoint event.
 648  *
 649  * For projects issued from a single company wishing to advertise that
 650  * the company controls the source code and thus the tracepoints, the
 651  * "com_" prefix should be used:
 652  *
 653  * either:
 654  *   com_company_project_component, event
 655  * or:
 656  *   com_company_project, event
 657  *
 658  * Where "company" is the name of the company,
 659  *       "project" is the name of the project,
 660  *       "component" is the name of the project component (which may
 661  *       include several levels of sub-components, e.g.
 662  *       ...component_subcomponent_...) where the tracepoint is located
 663  *       (optional),
 664  *       "event" is the name of the tracepoint event.
 665  *
 666  * the provider:event identifier is limited to 127 characters.
 667  */
 668
 669 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 670         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 671         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 672
 673 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 674
 675 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 676         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 677         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 678
 679 #endif /* #ifndef TRACEPOINT_EVENT */
 680
 681 #ifndef TRACEPOINT_LOGLEVEL
 682
 683 /*
 684  * Tracepoint Loglevels
 685  *
 686  * Typical use of these loglevels:
 687  *
 688  * The loglevels go from 0 to 14. Higher numbers imply the most
 689  * verbosity (higher event throughput expected.
 690  *
 691  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 692  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 693  * debug information.
 694  *
 695  * TRACE_EMERG           0
 696  * system is unusable
 697  *
 698  * TRACE_ALERT           1
 699  * action must be taken immediately
 700  *
 701  * TRACE_CRIT            2
 702  * critical conditions
 703  *
 704  * TRACE_ERR             3
 705  * error conditions
 706  *
 707  * TRACE_WARNING         4
 708  * warning conditions
 709  *
 710  * TRACE_NOTICE          5
 711  * normal, but significant, condition
 712  *
 713  * TRACE_INFO            6
 714  * informational message
 715  *
 716  * TRACE_DEBUG_SYSTEM    7
 717  * debug information with system-level scope (set of programs)
 718  *
 719  * TRACE_DEBUG_PROGRAM   8
 720  * debug information with program-level scope (set of processes)
 721  *
 722  * TRACE_DEBUG_PROCESS   9
 723  * debug information with process-level scope (set of modules)
 724  *
 725  * TRACE_DEBUG_MODULE    10
 726  * debug information with module (executable/library) scope (set of units)
 727  *
 728  * TRACE_DEBUG_UNIT      11
 729  * debug information with compilation unit scope (set of functions)
 730  *
 731  * TRACE_DEBUG_FUNCTION  12
 732  * debug information with function-level scope
 733  *
 734  * TRACE_DEBUG_LINE      13
 735  * debug information with line-level scope (TRACEPOINT_EVENT default)
 736  *
 737  * TRACE_DEBUG           14
 738  * debug-level message
 739  *
 740  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 741  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 742  * tracepoint name. The first field is the provider name, the second
 743  * field is the name of the tracepoint, the third field is the loglevel
 744  * name.
 745  *
 746  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 747  *              < loglevel_name >)
 748  *
 749  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 750  * TRACEPOINT_LOGLEVEL.
 751  */
 752
 753 enum {
 754         TRACE_EMERG             = 0,
 755         TRACE_ALERT             = 1,
 756         TRACE_CRIT              = 2,
 757         TRACE_ERR               = 3,
 758         TRACE_WARNING           = 4,
 759         TRACE_NOTICE            = 5,
 760         TRACE_INFO              = 6,
 761         TRACE_DEBUG_SYSTEM      = 7,
 762         TRACE_DEBUG_PROGRAM     = 8,
 763         TRACE_DEBUG_PROCESS     = 9,
 764         TRACE_DEBUG_MODULE      = 10,
 765         TRACE_DEBUG_UNIT        = 11,
 766         TRACE_DEBUG_FUNCTION    = 12,
 767         TRACE_DEBUG_LINE        = 13,
 768         TRACE_DEBUG             = 14,
 769 };
 770
 771 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 772
 773 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 774
 775 #ifndef TRACEPOINT_MODEL_EMF_URI
 776
 777 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 778
 779 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */