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 struct lttng_ust_tracepoint_dlopen {
 215         void *liblttngust_handle;
 216
 217         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 218                 int tracepoints_count);
 219         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 220         void (*rcu_read_lock_sym)(void);
 221         void (*rcu_read_unlock_sym)(void);
 222         void *(*rcu_dereference_sym)(void *p);
 223 };
 224
 225 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 226 extern struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr;
 227
 228 /*
 229  * These weak symbols, the constructor, and destructor take care of
 230  * registering only _one_ instance of the tracepoints per shared-ojbect
 231  * (or for the whole main program).
 232  */
 233 int __tracepoint_registered
 234         __attribute__((weak, visibility("hidden")));
 235 int __tracepoint_ptrs_registered
 236         __attribute__((weak, visibility("hidden")));
 237 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 238         __attribute__((weak, visibility("hidden")));
 239 /*
 240  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 241  * 4.8 and prior does not have the same behavior for symbol scoping on
 242  * 32-bit powerpc depending on the object size: symbols for objects of 8
 243  * bytes or less have the same address throughout a module, whereas they
 244  * have different addresses between compile units for objects larger
 245  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 246  * scoping match that of the other weak hidden symbols found in this
 247  * header.
 248  */
 249 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 250         __attribute__((weak, visibility("hidden")));
 251
 252 /*
 253  * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared
 254  * across objects in a module/main executable. The callbacks are used to
 255  * control and check if the destructors should be executed.
 256  */
 257 struct lttng_ust_tracepoint_destructors_syms {
 258         void (*tracepoint_disable_destructors)(void);
 259         int (*tracepoint_get_destructors_state)(void);
 260 };
 261
 262 extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms;
 263 extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr;
 264
 265 struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms
 266         __attribute__((weak, visibility("hidden")));
 267 struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr
 268         __attribute__((weak, visibility("hidden")));
 269
 270 static inline void tracepoint_disable_destructors(void)
 271 {
 272         if (!tracepoint_dlopen_ptr)
 273                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 274         if (!tracepoint_destructors_syms_ptr)
 275                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 276         if (tracepoint_dlopen_ptr->liblttngust_handle
 277                         && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors)
 278                 tracepoint_destructors_syms_ptr->tracepoint_disable_destructors();
 279 }
 280
 281 #ifndef _LGPL_SOURCE
 282 static inline void lttng_ust_notrace
 283 __tracepoint__init_urcu_sym(void);
 284 static inline void
 285 __tracepoint__init_urcu_sym(void)
 286 {
 287         if (!tracepoint_dlopen_ptr)
 288                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 289         /*
 290          * Symbols below are needed by tracepoint call sites and probe
 291          * providers.
 292          */
 293         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym)
 294                 tracepoint_dlopen_ptr->rcu_read_lock_sym =
 295                         URCU_FORCE_CAST(void (*)(void),
 296                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 297                                         "tp_rcu_read_lock"));
 298         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym)
 299                 tracepoint_dlopen_ptr->rcu_read_unlock_sym =
 300                         URCU_FORCE_CAST(void (*)(void),
 301                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 302                                         "tp_rcu_read_unlock"));
 303         if (!tracepoint_dlopen_ptr->rcu_dereference_sym)
 304                 tracepoint_dlopen_ptr->rcu_dereference_sym =
 305                         URCU_FORCE_CAST(void *(*)(void *p),
 306                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 307                                         "tp_rcu_dereference_sym"));
 308 }
 309 #else
 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 }
 316 #endif
 317
 318 static void lttng_ust_notrace __attribute__((constructor))
 319 __tracepoints__init(void);
 320 static void
 321 __tracepoints__init(void)
 322 {
 323         if (__tracepoint_registered++) {
 324                 if (!tracepoint_dlopen_ptr->liblttngust_handle)
 325                         return;
 326                 __tracepoint__init_urcu_sym();
 327                 return;
 328         }
 329
 330         if (!tracepoint_dlopen_ptr)
 331                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 332         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 333                 tracepoint_dlopen_ptr->liblttngust_handle =
 334                         dlopen("liblttng-ust-tracepoint.so.1", RTLD_NOW | RTLD_GLOBAL);
 335         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 336                 return;
 337         __tracepoint__init_urcu_sym();
 338 }
 339
 340 static void lttng_ust_notrace __attribute__((destructor))
 341 __tracepoints__destroy(void);
 342 static void
 343 __tracepoints__destroy(void)
 344 {
 345         int ret;
 346
 347         if (--__tracepoint_registered)
 348                 return;
 349         if (!tracepoint_dlopen_ptr)
 350                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 351         if (!tracepoint_destructors_syms_ptr)
 352                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 353         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 354                 return;
 355         if (__tracepoint_ptrs_registered)
 356                 return;
 357         /*
 358          * Lookup if destructors must be executed using the new method.
 359          */
 360         if (tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 361                 && !tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()) {
 362                 /*
 363                  * The tracepoint_get_destructors_state symbol was found with
 364                  * dlsym but its returned value is 0 meaning that destructors
 365                  * must not be executed.
 366                  */
 367                 return;
 368         }
 369         ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 370         if (ret) {
 371                 fprintf(stderr, "Error (%d) in dlclose\n", ret);
 372                 abort();
 373         }
 374         memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 375 }
 376
 377 #ifdef TRACEPOINT_DEFINE
 378
 379 /*
 380  * These weak symbols, the constructor, and destructor take care of
 381  * registering only _one_ instance of the tracepoints per shared-ojbect
 382  * (or for the whole main program).
 383  */
 384 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 385         __attribute__((weak, visibility("hidden")));
 386 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 387         __attribute__((weak, visibility("hidden")));
 388
 389 /*
 390  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 391  * unresolved symbol that requires the provider to be linked in. When
 392  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 393  * unresolved symbol that depends on having the provider linked in,
 394  * otherwise the linker complains. This deals with use of static
 395  * libraries, ensuring that the linker does not remove the provider
 396  * object from the executable.
 397  */
 398 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 399 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 400 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 401 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 402 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 403
 404 /*
 405  * Note: to allow PIC code, we need to allow the linker to update the pointers
 406  * in the __tracepoints_ptrs section.
 407  * Therefore, this section is _not_ const (read-only).
 408  */
 409 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 410
 411 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 412         extern int __tracepoint_provider_##_provider;                           \
 413         static const char __tp_strtab_##_provider##___##_name[]                 \
 414                 __attribute__((section("__tracepoints_strings"))) =             \
 415                         #_provider ":" #_name;                                  \
 416         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 417                 __attribute__((section("__tracepoints"))) =                     \
 418                 {                                                               \
 419                         __tp_strtab_##_provider##___##_name,                    \
 420                         0,                                                      \
 421                         NULL,                                                   \
 422                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 423                         _TP_EXTRACT_STRING(_args),                              \
 424                         { },                                                    \
 425                 };                                                              \
 426         static struct lttng_ust_tracepoint *                                    \
 427                 __tracepoint_ptr_##_provider##___##_name                        \
 428                 __attribute__((section("__tracepoints_ptrs"), used))            \
 429                 __lttng_ust_variable_attribute_no_sanitize_address =            \
 430                         &__tracepoint_##_provider##___##_name;
 431
 432 static void lttng_ust_notrace __attribute__((constructor))
 433 __tracepoints__ptrs_init(void);
 434 static void
 435 __tracepoints__ptrs_init(void)
 436 {
 437         if (__tracepoint_ptrs_registered++)
 438                 return;
 439         if (!tracepoint_dlopen_ptr)
 440                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 441         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 442                 tracepoint_dlopen_ptr->liblttngust_handle =
 443                         dlopen("liblttng-ust-tracepoint.so.1", RTLD_NOW | RTLD_GLOBAL);
 444         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 445                 return;
 446         if (!tracepoint_destructors_syms_ptr)
 447                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 448         tracepoint_dlopen_ptr->tracepoint_register_lib =
 449                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 450                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 451                                         "tracepoint_register_lib"));
 452         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 453                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 454                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 455                                         "tracepoint_unregister_lib"));
 456         tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
 457                 URCU_FORCE_CAST(void (*)(void),
 458                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 459                                         "tp_disable_destructors"));
 460         tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state =
 461                 URCU_FORCE_CAST(int (*)(void),
 462                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 463                                         "tp_get_destructors_state"));
 464         __tracepoint__init_urcu_sym();
 465         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 466                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 467                                 __stop___tracepoints_ptrs -
 468                                 __start___tracepoints_ptrs);
 469         }
 470 }
 471
 472 static void lttng_ust_notrace __attribute__((destructor))
 473 __tracepoints__ptrs_destroy(void);
 474 static void
 475 __tracepoints__ptrs_destroy(void)
 476 {
 477         int ret;
 478
 479         if (--__tracepoint_ptrs_registered)
 480                 return;
 481         if (!tracepoint_dlopen_ptr)
 482                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 483         if (!tracepoint_destructors_syms_ptr)
 484                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 485         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 486                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 487         if (tracepoint_dlopen_ptr->liblttngust_handle
 488                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 489                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
 490                         && !__tracepoint_ptrs_registered) {
 491                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 492                 if (ret) {
 493                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 494                         abort();
 495                 }
 496                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 497         }
 498 }
 499
 500 #else /* TRACEPOINT_DEFINE */
 501
 502 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 503
 504 #endif /* #else TRACEPOINT_DEFINE */
 505
 506 #ifdef __cplusplus
 507 }
 508 #endif
 509
 510 #endif /* _LTTNG_TRACEPOINT_H */
 511
 512 /* The following declarations must be outside re-inclusion protection. */
 513
 514 #ifndef TRACEPOINT_ENUM
 515
 516 /*
 517  * Tracepoint Enumerations
 518  *
 519  * The enumeration is a mapping between an integer, or range of integers, and
 520  * a string. It can be used to have a more compact trace in cases where the
 521  * possible values for a field are limited:
 522  *
 523  * An example:
 524  *
 525  * TRACEPOINT_ENUM(someproject_component, enumname,
 526  *      TP_ENUM_VALUES(
 527  *              ctf_enum_value("even", 0)
 528  *              ctf_enum_value("uneven", 1)
 529  *              ctf_enum_range("twoto4", 2, 4)
 530  *              ctf_enum_value("five", 5)
 531  *      )
 532  * )
 533  *
 534  * Where "someproject_component" is the name of the component this enumeration
 535  * belongs to and "enumname" identifies this enumeration. Inside the
 536  * TP_ENUM_VALUES macro is the actual mapping. Each string value can map
 537  * to either a single value with ctf_enum_value or a range of values
 538  * with ctf_enum_range.
 539  *
 540  * Enumeration ranges may overlap, but the behavior is implementation-defined,
 541  * each trace reader will handle overlapping as it wishes.
 542  *
 543  * That enumeration can then be used in a field inside the TP_FIELD macro using
 544  * the following line:
 545  *
 546  * ctf_enum(someproject_component, enumname, enumtype, enumfield, enumval)
 547  *
 548  * Where "someproject_component" and "enumname" match those in the
 549  * TRACEPOINT_ENUM, "enumtype" is a signed or unsigned integer type
 550  * backing the enumeration, "enumfield" is the name of the field and
 551  * "enumval" is the value.
 552  */
 553
 554 #define TRACEPOINT_ENUM(provider, name, values)
 555
 556 #endif /* #ifndef TRACEPOINT_ENUM */
 557
 558 #ifndef TRACEPOINT_EVENT
 559
 560 /*
 561  * How to use the TRACEPOINT_EVENT macro:
 562  *
 563  * An example:
 564  *
 565  * TRACEPOINT_EVENT(someproject_component, event_name,
 566  *
 567  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 568  *
 569  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 570  *             long *, arg4, size_t, arg4_len),
 571  *
 572  *      * TP_FIELDS describes the event payload layout in the trace *
 573  *
 574  *     TP_FIELDS(
 575  *         * Integer, printed in base 10 *
 576  *         ctf_integer(int, field_a, arg0)
 577  *
 578  *         * Integer, printed with 0x base 16 *
 579  *         ctf_integer_hex(unsigned long, field_d, arg1)
 580  *
 581  *         * Enumeration *
 582  *         ctf_enum(someproject_component, enum_name, int, field_e, arg0)
 583  *
 584  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 585  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 586  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 587  *
 588  *         * String, printed as UTF8-encoded string *
 589  *         ctf_string(field_e, string)
 590  *
 591  *         * Array sequence of signed integer values *
 592  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 593  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 594  *     )
 595  * )
 596  *
 597  * More detailed explanation:
 598  *
 599  * The name of the tracepoint is expressed as a tuple with the provider
 600  * and name arguments.
 601  *
 602  * The provider and name should be a proper C99 identifier.
 603  * The "provider" and "name" MUST follow these rules to ensure no
 604  * namespace clash occurs:
 605  *
 606  * For projects (applications and libraries) for which an entity
 607  * specific to the project controls the source code and thus its
 608  * tracepoints (typically with a scope larger than a single company):
 609  *
 610  * either:
 611  *   project_component, event
 612  * or:
 613  *   project, event
 614  *
 615  * Where "project" is the name of the project,
 616  *       "component" is the name of the project component (which may
 617  *       include several levels of sub-components, e.g.
 618  *       ...component_subcomponent_...) where the tracepoint is located
 619  *       (optional),
 620  *       "event" is the name of the tracepoint event.
 621  *
 622  * For projects issued from a single company wishing to advertise that
 623  * the company controls the source code and thus the tracepoints, the
 624  * "com_" prefix should be used:
 625  *
 626  * either:
 627  *   com_company_project_component, event
 628  * or:
 629  *   com_company_project, event
 630  *
 631  * Where "company" is the name of the company,
 632  *       "project" is the name of the project,
 633  *       "component" is the name of the project component (which may
 634  *       include several levels of sub-components, e.g.
 635  *       ...component_subcomponent_...) where the tracepoint is located
 636  *       (optional),
 637  *       "event" is the name of the tracepoint event.
 638  *
 639  * the provider:event identifier is limited to 127 characters.
 640  */
 641
 642 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 643         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 644         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 645
 646 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 647
 648 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 649         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 650         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 651
 652 #endif /* #ifndef TRACEPOINT_EVENT */
 653
 654 #ifndef TRACEPOINT_LOGLEVEL
 655
 656 /*
 657  * Tracepoint Loglevels
 658  *
 659  * Typical use of these loglevels:
 660  *
 661  * The loglevels go from 0 to 14. Higher numbers imply the most
 662  * verbosity (higher event throughput expected.
 663  *
 664  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 665  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 666  * debug information.
 667  *
 668  * TRACE_EMERG           0
 669  * system is unusable
 670  *
 671  * TRACE_ALERT           1
 672  * action must be taken immediately
 673  *
 674  * TRACE_CRIT            2
 675  * critical conditions
 676  *
 677  * TRACE_ERR             3
 678  * error conditions
 679  *
 680  * TRACE_WARNING         4
 681  * warning conditions
 682  *
 683  * TRACE_NOTICE          5
 684  * normal, but significant, condition
 685  *
 686  * TRACE_INFO            6
 687  * informational message
 688  *
 689  * TRACE_DEBUG_SYSTEM    7
 690  * debug information with system-level scope (set of programs)
 691  *
 692  * TRACE_DEBUG_PROGRAM   8
 693  * debug information with program-level scope (set of processes)
 694  *
 695  * TRACE_DEBUG_PROCESS   9
 696  * debug information with process-level scope (set of modules)
 697  *
 698  * TRACE_DEBUG_MODULE    10
 699  * debug information with module (executable/library) scope (set of units)
 700  *
 701  * TRACE_DEBUG_UNIT      11
 702  * debug information with compilation unit scope (set of functions)
 703  *
 704  * TRACE_DEBUG_FUNCTION  12
 705  * debug information with function-level scope
 706  *
 707  * TRACE_DEBUG_LINE      13
 708  * debug information with line-level scope (TRACEPOINT_EVENT default)
 709  *
 710  * TRACE_DEBUG           14
 711  * debug-level message
 712  *
 713  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 714  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 715  * tracepoint name. The first field is the provider name, the second
 716  * field is the name of the tracepoint, the third field is the loglevel
 717  * name.
 718  *
 719  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 720  *              < loglevel_name >)
 721  *
 722  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 723  * TRACEPOINT_LOGLEVEL.
 724  */
 725
 726 enum {
 727         TRACE_EMERG             = 0,
 728         TRACE_ALERT             = 1,
 729         TRACE_CRIT              = 2,
 730         TRACE_ERR               = 3,
 731         TRACE_WARNING           = 4,
 732         TRACE_NOTICE            = 5,
 733         TRACE_INFO              = 6,
 734         TRACE_DEBUG_SYSTEM      = 7,
 735         TRACE_DEBUG_PROGRAM     = 8,
 736         TRACE_DEBUG_PROCESS     = 9,
 737         TRACE_DEBUG_MODULE      = 10,
 738         TRACE_DEBUG_UNIT        = 11,
 739         TRACE_DEBUG_FUNCTION    = 12,
 740         TRACE_DEBUG_LINE        = 13,
 741         TRACE_DEBUG             = 14,
 742 };
 743
 744 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 745
 746 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 747
 748 #ifndef TRACEPOINT_MODEL_EMF_URI
 749
 750 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 751
 752 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */