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 #include <lttng/ust-api-compat.h>
  23
  24 #define LTTNG_UST_TRACEPOINT_NAME_LEN_MAX       256
  25
  26 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  27 /*
  28  * Instead of using SDT_USE_VARIADIC from 'sys/sdt.h', use our own namespaced
  29  * macros since the instrumented application might already have included
  30  * 'sys/sdt.h' without variadic support.
  31  */
  32 #include <sys/sdt.h>
  33
  34 #define _LTTNG_UST_SDT_NARG(...) \
  35         __LTTNG_UST_SDT_NARG(__VA_ARGS__, 12,11,10,9,8,7,6,5,4,3,2,1,0)
  36
  37 #define __LTTNG_UST_SDT_NARG(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12, N, ...) N
  38
  39 #define _LTTNG_UST_SDT_PROBE_N(provider, name, N, ...) \
  40         _SDT_PROBE(provider, name, N, (__VA_ARGS__))
  41
  42 #define LTTNG_UST_STAP_PROBEV(provider, name, ...) \
  43         _LTTNG_UST_SDT_PROBE_N(provider, name, _LTTNG_UST_SDT_NARG(0, ##__VA_ARGS__), ##__VA_ARGS__)
  44
  45 #else
  46 #define LTTNG_UST_STAP_PROBEV(...)
  47 #endif
  48
  49 #ifdef __cplusplus
  50 extern "C" {
  51 #endif
  52
  53 #define lttng_ust_tracepoint_enabled(provider, name)                            \
  54         caa_unlikely(CMM_LOAD_SHARED(__tracepoint_##provider##___##name.state))
  55
  56 #define lttng_ust_do_tracepoint(provider, name, ...)                            \
  57         __tracepoint_cb_##provider##___##name(__VA_ARGS__)
  58
  59 #define lttng_ust_tracepoint(provider, name, ...)                               \
  60         do {                                                                    \
  61                 LTTNG_UST_STAP_PROBEV(provider, name, ## __VA_ARGS__);          \
  62                 if (lttng_ust_tracepoint_enabled(provider, name))               \
  63                         lttng_ust_do_tracepoint(provider, name, __VA_ARGS__);   \
  64         } while (0)
  65
  66 #define LTTNG_UST_TP_ARGS(...)       __VA_ARGS__
  67
  68 /*
  69  * LTTNG_UST_TP_ARGS takes tuples of type, argument separated by a comma.
  70  * It can take up to 10 tuples (which means that less than 10 tuples is
  71  * fine too).
  72  * Each tuple is also separated by a comma.
  73  */
  74 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  75                 _tokena##_tokenb
  76 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  77                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  78 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  79                 _tokena##_tokenb##_tokenc
  80 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  81                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  82 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  83                 _tokena##_tokenb##_tokenc##_tokend
  84 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  85                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  86
  87 /*
  88  * _TP_EXVAR* extract the var names.
  89  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  90  */
  91 #define _TP_EXVAR0()
  92 #define _TP_EXVAR1(a)
  93 #define _TP_EXVAR2(a,b)                                         b
  94 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  95 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  96 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  97 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  98 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  99 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
 100 #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
 101 #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
 102 #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
 103
 104 #define _TP_EXDATA_VAR0()                                               __tp_data
 105 #define _TP_EXDATA_VAR1(a)                                              __tp_data
 106 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
 107 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
 108 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
 109 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
 110 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
 111 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 112 #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
 113 #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
 114 #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
 115 #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
 116
 117 /*
 118  * _TP_EXPROTO* extract tuples of type, var.
 119  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 120  */
 121 #define _TP_EXPROTO0()                                          void
 122 #define _TP_EXPROTO1(a)                                         void
 123 #define _TP_EXPROTO2(a,b)                                       a b
 124 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 125 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 126 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 127 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 128 #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
 129 #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
 130 #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
 131 #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
 132 #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
 133
 134 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 135 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 136 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 137 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 138 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 139 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 140 #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
 141 #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
 142 #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
 143 #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
 144 #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
 145 #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
 146
 147 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 148 #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)
 149 #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
 150 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 151 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 152 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 153 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 154 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 155 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 156 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 157 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 158 #define _TP_PARAMS(...)                 __VA_ARGS__
 159
 160 /*
 161  * sizeof(#_provider) - 1 : length of the provider string (excluding \0).
 162  * sizeof(#_name) - 1     : length of the name string (excluding \0).
 163  * + 1                    : separator between provider and event name.
 164  *
 165  * Upper bound (inclusive) is LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1 to
 166  * account for \0.
 167  *
 168  * The comparison is:
 169  *   left hand side:   sizeof(#_provider) - 1 + sizeof(#_name) - 1 + 1
 170  *   right hand side:  LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1
 171  *   operator:         <=  (inclusive)
 172  * Simplified in the code below.
 173  */
 174 #define lttng_ust_tracepoint_validate_name_len(_provider, _name)                                                \
 175         lttng_ust_static_assert(sizeof(#_provider) + sizeof(#_name) <= LTTNG_UST_TRACEPOINT_NAME_LEN_MAX,       \
 176                 "Tracepoint name length is too long",                                                           \
 177                 Tracepoint_name_length_is_too_long)
 178
 179 /*
 180  * The tracepoint cb is marked always inline so we can distinguish
 181  * between caller's ip addresses within the probe using the return
 182  * address.
 183  */
 184 #define LTTNG_UST__DECLARE_TRACEPOINT(_provider, _name, ...)                                    \
 185 extern struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name;                \
 186 static inline                                                                           \
 187 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 188         __attribute__((always_inline, unused)) lttng_ust_notrace;                       \
 189 static                                                                                  \
 190 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 191 {                                                                                       \
 192         struct lttng_ust_tracepoint_probe *__tp_probe;                                  \
 193                                                                                         \
 194         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 195                 return;                                                                 \
 196         tp_rcu_read_lock();                                                             \
 197         __tp_probe = tp_rcu_dereference(__tracepoint_##_provider##___##_name.probes);   \
 198         if (caa_unlikely(!__tp_probe))                                                  \
 199                 goto end;                                                               \
 200         do {                                                                            \
 201                 void (*__tp_cb)(void) = __tp_probe->func;                               \
 202                 void *__tp_data = __tp_probe->data;                                     \
 203                                                                                         \
 204                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 205                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 206         } while ((++__tp_probe)->func);                                                 \
 207 end:                                                                                    \
 208         tp_rcu_read_unlock();                                                           \
 209 }                                                                                       \
 210 static inline                                                                           \
 211 void __tracepoint_register_##_provider##___##_name(char *provider_name, char *event_name, \
 212                 void (*func)(void), void *data)                                         \
 213         lttng_ust_notrace;                                                              \
 214 static inline                                                                           \
 215 void __tracepoint_register_##_provider##___##_name(char *provider_name, char *event_name, \
 216                 void (*func)(void), void *data)                                         \
 217 {                                                                                       \
 218         __tracepoint_probe_register(provider_name, event_name, func, data,              \
 219                 __tracepoint_##_provider##___##_name.signature);                        \
 220 }                                                                                       \
 221 static inline                                                                           \
 222 void __tracepoint_unregister_##_provider##___##_name(char *provider_name, char *event_name, \
 223                 void (*func)(void), void *data)                                         \
 224         lttng_ust_notrace;                                                              \
 225 static inline                                                                           \
 226 void __tracepoint_unregister_##_provider##___##_name(char *provider_name, char *event_name, \
 227                 void (*func)(void), void *data)                                         \
 228 {                                                                                       \
 229         __tracepoint_probe_unregister(provider_name, event_name, func, data);           \
 230 }
 231
 232 extern int __tracepoint_probe_register(const char *provider_name, const char *event_name,
 233                 void (*func)(void), void *data, const char *signature);
 234 extern int __tracepoint_probe_unregister(const char *provider_name, const char *event_name,
 235                 void (*func)(void), void *data);
 236
 237 /*
 238  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 239  * shared across objects in a module/main executable.
 240  *
 241  * IMPORTANT: this structure is part of the ABI between instrumented
 242  * applications and UST. Fields need to be only added at the end, never
 243  * reordered, never removed.
 244  *
 245  * The field @struct_size should be used to determine the size of the
 246  * structure. It should be queried before using additional fields added
 247  * at the end of the structure.
 248  */
 249 struct lttng_ust_tracepoint_dlopen {
 250         uint32_t struct_size;
 251
 252         void *liblttngust_handle;
 253
 254         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 255                 int tracepoints_count);
 256         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 257         void (*rcu_read_lock_sym)(void);
 258         void (*rcu_read_unlock_sym)(void);
 259         void *(*rcu_dereference_sym)(void *p);
 260
 261         /* End of base ABI. Fields below should be used after checking struct_size. */
 262 };
 263
 264 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 265 extern struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr;
 266
 267 /*
 268  * These weak symbols, the constructor, and destructor take care of
 269  * registering only _one_ instance of the tracepoints per shared-ojbect
 270  * (or for the whole main program).
 271  */
 272 int __tracepoint_registered
 273         __attribute__((weak, visibility("hidden")));
 274 int __tracepoint_ptrs_registered
 275         __attribute__((weak, visibility("hidden")));
 276 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 277                 __attribute__((weak, visibility("hidden"))) = {
 278         .struct_size = sizeof(struct lttng_ust_tracepoint_dlopen),
 279 };
 280 /*
 281  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 282  * 4.8 and prior does not have the same behavior for symbol scoping on
 283  * 32-bit powerpc depending on the object size: symbols for objects of 8
 284  * bytes or less have the same address throughout a module, whereas they
 285  * have different addresses between compile units for objects larger
 286  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 287  * scoping match that of the other weak hidden symbols found in this
 288  * header.
 289  */
 290 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 291         __attribute__((weak, visibility("hidden")));
 292
 293 /*
 294  * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared
 295  * across objects in a module/main executable. The callbacks are used to
 296  * control and check if the destructors should be executed.
 297  *
 298  * IMPORTANT: this structure is part of the ABI between instrumented
 299  * applications and UST. Fields need to be only added at the end, never
 300  * reordered, never removed.
 301  *
 302  * The field @struct_size should be used to determine the size of the
 303  * structure. It should be queried before using additional fields added
 304  * at the end of the structure.
 305  */
 306 struct lttng_ust_tracepoint_destructors_syms {
 307         uint32_t struct_size;
 308
 309         void (*tracepoint_disable_destructors)(void);
 310         int (*tracepoint_get_destructors_state)(void);
 311
 312         /* End of base ABI. Fields below should be used after checking struct_size. */
 313 };
 314
 315 extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms;
 316 extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr;
 317
 318 struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms
 319         __attribute__((weak, visibility("hidden"))) = {
 320         .struct_size = sizeof(struct lttng_ust_tracepoint_destructors_syms),
 321 };
 322 struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr
 323         __attribute__((weak, visibility("hidden")));
 324
 325 static inline void tracepoint_disable_destructors(void)
 326 {
 327         if (!tracepoint_dlopen_ptr)
 328                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 329         if (!tracepoint_destructors_syms_ptr)
 330                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 331         if (tracepoint_dlopen_ptr->liblttngust_handle
 332                         && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors)
 333                 tracepoint_destructors_syms_ptr->tracepoint_disable_destructors();
 334 }
 335
 336 #ifndef _LGPL_SOURCE
 337 static inline void
 338 __tracepoint__init_urcu_sym(void)
 339         lttng_ust_notrace;
 340 static inline void
 341 __tracepoint__init_urcu_sym(void)
 342 {
 343         if (!tracepoint_dlopen_ptr)
 344                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 345         /*
 346          * Symbols below are needed by tracepoint call sites and probe
 347          * providers.
 348          */
 349         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym)
 350                 tracepoint_dlopen_ptr->rcu_read_lock_sym =
 351                         URCU_FORCE_CAST(void (*)(void),
 352                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 353                                         "tp_rcu_read_lock"));
 354         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym)
 355                 tracepoint_dlopen_ptr->rcu_read_unlock_sym =
 356                         URCU_FORCE_CAST(void (*)(void),
 357                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 358                                         "tp_rcu_read_unlock"));
 359         if (!tracepoint_dlopen_ptr->rcu_dereference_sym)
 360                 tracepoint_dlopen_ptr->rcu_dereference_sym =
 361                         URCU_FORCE_CAST(void *(*)(void *p),
 362                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 363                                         "tp_rcu_dereference_sym"));
 364 }
 365 #else
 366 static inline void
 367 __tracepoint__init_urcu_sym(void)
 368         lttng_ust_notrace;
 369 static inline void
 370 __tracepoint__init_urcu_sym(void)
 371 {
 372 }
 373 #endif
 374
 375 static void
 376 __tracepoints__init(void)
 377         lttng_ust_notrace __attribute__((constructor));
 378 static void
 379 __tracepoints__init(void)
 380 {
 381         if (__tracepoint_registered++) {
 382                 if (!tracepoint_dlopen_ptr->liblttngust_handle)
 383                         return;
 384                 __tracepoint__init_urcu_sym();
 385                 return;
 386         }
 387
 388         if (!tracepoint_dlopen_ptr)
 389                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 390         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 391                 tracepoint_dlopen_ptr->liblttngust_handle =
 392                         dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
 393         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 394                 return;
 395         __tracepoint__init_urcu_sym();
 396 }
 397
 398 static void
 399 __tracepoints__destroy(void)
 400         lttng_ust_notrace __attribute__((destructor));
 401 static void
 402 __tracepoints__destroy(void)
 403 {
 404         int ret;
 405
 406         if (--__tracepoint_registered)
 407                 return;
 408         if (!tracepoint_dlopen_ptr)
 409                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 410         if (!tracepoint_destructors_syms_ptr)
 411                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 412         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 413                 return;
 414         if (__tracepoint_ptrs_registered)
 415                 return;
 416         /*
 417          * Lookup if destructors must be executed using the new method.
 418          */
 419         if (tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 420                 && !tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()) {
 421                 /*
 422                  * The tracepoint_get_destructors_state symbol was found with
 423                  * dlsym but its returned value is 0 meaning that destructors
 424                  * must not be executed.
 425                  */
 426                 return;
 427         }
 428         ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 429         if (ret) {
 430                 fprintf(stderr, "Error (%d) in dlclose\n", ret);
 431                 abort();
 432         }
 433         memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 434 }
 435
 436 #ifdef TRACEPOINT_DEFINE
 437
 438 /*
 439  * These weak symbols, the constructor, and destructor take care of
 440  * registering only _one_ instance of the tracepoints per shared-ojbect
 441  * (or for the whole main program).
 442  */
 443 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 444         __attribute__((weak, visibility("hidden")));
 445 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 446         __attribute__((weak, visibility("hidden")));
 447
 448 /*
 449  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 450  * unresolved symbol that requires the provider to be linked in. When
 451  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 452  * unresolved symbol that depends on having the provider linked in,
 453  * otherwise the linker complains. This deals with use of static
 454  * libraries, ensuring that the linker does not remove the provider
 455  * object from the executable.
 456  */
 457 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 458 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 459 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 460 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 461 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 462
 463 /*
 464  * Note: to allow PIC code, we need to allow the linker to update the pointers
 465  * in the __tracepoints_ptrs section.
 466  * Therefore, this section is _not_ const (read-only).
 467  */
 468 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 469
 470 #define LTTNG_UST__DEFINE_TRACEPOINT(_provider, _name, _args)                           \
 471         lttng_ust_tracepoint_validate_name_len(_provider, _name);               \
 472         extern int __tracepoint_provider_##_provider;                           \
 473         static const char __tp_provider_strtab_##_provider##___##_name[]        \
 474                 __attribute__((section("__tracepoints_strings"))) =             \
 475                         #_provider;                                             \
 476         static const char __tp_name_strtab_##_provider##___##_name[]            \
 477                 __attribute__((section("__tracepoints_strings"))) =             \
 478                         #_name;                                                 \
 479         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 480                 __attribute__((section("__tracepoints"))) = {                   \
 481                         sizeof(struct lttng_ust_tracepoint),                    \
 482                         __tp_provider_strtab_##_provider##___##_name,           \
 483                         __tp_name_strtab_##_provider##___##_name,               \
 484                         0,                                                      \
 485                         NULL,                                                   \
 486                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 487                         _TP_EXTRACT_STRING(_args),                              \
 488                 };                                                              \
 489         static struct lttng_ust_tracepoint *                                    \
 490                 __tracepoint_ptr_##_provider##___##_name                        \
 491                 __attribute__((section("__tracepoints_ptrs"), used))            \
 492                 __lttng_ust_variable_attribute_no_sanitize_address =            \
 493                         &__tracepoint_##_provider##___##_name;
 494
 495 static void
 496 __tracepoints__ptrs_init(void)
 497         lttng_ust_notrace __attribute__((constructor));
 498 static void
 499 __tracepoints__ptrs_init(void)
 500 {
 501         if (__tracepoint_ptrs_registered++)
 502                 return;
 503         if (!tracepoint_dlopen_ptr)
 504                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 505         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 506                 tracepoint_dlopen_ptr->liblttngust_handle =
 507                         dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
 508         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 509                 return;
 510         if (!tracepoint_destructors_syms_ptr)
 511                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 512         tracepoint_dlopen_ptr->tracepoint_register_lib =
 513                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 514                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 515                                         "tracepoint_register_lib"));
 516         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 517                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 518                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 519                                         "tracepoint_unregister_lib"));
 520         tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
 521                 URCU_FORCE_CAST(void (*)(void),
 522                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 523                                         "tp_disable_destructors"));
 524         tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state =
 525                 URCU_FORCE_CAST(int (*)(void),
 526                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 527                                         "tp_get_destructors_state"));
 528         __tracepoint__init_urcu_sym();
 529         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 530                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 531                                 __stop___tracepoints_ptrs -
 532                                 __start___tracepoints_ptrs);
 533         }
 534 }
 535
 536 static void
 537 __tracepoints__ptrs_destroy(void)
 538         lttng_ust_notrace __attribute__((destructor));
 539 static void
 540 __tracepoints__ptrs_destroy(void)
 541 {
 542         int ret;
 543
 544         if (--__tracepoint_ptrs_registered)
 545                 return;
 546         if (!tracepoint_dlopen_ptr)
 547                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 548         if (!tracepoint_destructors_syms_ptr)
 549                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 550         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 551                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 552         if (tracepoint_dlopen_ptr->liblttngust_handle
 553                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 554                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
 555                         && !__tracepoint_ptrs_registered) {
 556                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 557                 if (ret) {
 558                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 559                         abort();
 560                 }
 561                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 562         }
 563 }
 564
 565 #else /* TRACEPOINT_DEFINE */
 566
 567 #define LTTNG_UST__DEFINE_TRACEPOINT(_provider, _name, _args)
 568
 569 #endif /* #else TRACEPOINT_DEFINE */
 570
 571 #if LTTNG_UST_COMPAT_API(0)
 572 #define tracepoint                      lttng_ust_tracepoint
 573 #define do_tracepoint                   lttng_ust_do_tracepoint
 574 #define tracepoint_enabled              lttng_ust_tracepoint_enabled
 575 #define TP_ARGS                         LTTNG_UST_TP_ARGS
 576 #define TP_FIELDS                       LTTNG_UST_TP_FIELDS
 577 #endif /* #if LTTNG_UST_COMPAT_API(0) */
 578
 579 #ifdef __cplusplus
 580 }
 581 #endif
 582
 583 #endif /* _LTTNG_TRACEPOINT_H */
 584
 585 /* The following declarations must be outside re-inclusion protection. */
 586
 587 #ifndef TRACEPOINT_ENUM
 588
 589 /*
 590  * Tracepoint Enumerations
 591  *
 592  * The enumeration is a mapping between an integer, or range of integers, and
 593  * a string. It can be used to have a more compact trace in cases where the
 594  * possible values for a field are limited:
 595  *
 596  * An example:
 597  *
 598  * TRACEPOINT_ENUM(someproject_component, enumname,
 599  *      TP_ENUM_VALUES(
 600  *              ctf_enum_value("even", 0)
 601  *              ctf_enum_value("uneven", 1)
 602  *              ctf_enum_range("twoto4", 2, 4)
 603  *              ctf_enum_value("five", 5)
 604  *      )
 605  * )
 606  *
 607  * Where "someproject_component" is the name of the component this enumeration
 608  * belongs to and "enumname" identifies this enumeration. Inside the
 609  * TP_ENUM_VALUES macro is the actual mapping. Each string value can map
 610  * to either a single value with ctf_enum_value or a range of values
 611  * with ctf_enum_range.
 612  *
 613  * Enumeration ranges may overlap, but the behavior is implementation-defined,
 614  * each trace reader will handle overlapping as it wishes.
 615  *
 616  * That enumeration can then be used in a field inside the TP_FIELD macro using
 617  * the following line:
 618  *
 619  * ctf_enum(someproject_component, enumname, enumtype, enumfield, enumval)
 620  *
 621  * Where "someproject_component" and "enumname" match those in the
 622  * TRACEPOINT_ENUM, "enumtype" is a signed or unsigned integer type
 623  * backing the enumeration, "enumfield" is the name of the field and
 624  * "enumval" is the value.
 625  */
 626
 627 #define TRACEPOINT_ENUM(provider, name, values)
 628
 629 #endif /* #ifndef TRACEPOINT_ENUM */
 630
 631 #ifndef LTTNG_UST_TRACEPOINT_EVENT
 632
 633 /*
 634  * How to use the LTTNG_UST_TRACEPOINT_EVENT macro:
 635  *
 636  * An example:
 637  *
 638  * LTTNG_UST_TRACEPOINT_EVENT(someproject_component, event_name,
 639  *
 640  *     * LTTNG_UST_TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 641  *
 642  *     LTTNG_UST_TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 643  *             long *, arg4, size_t, arg4_len),
 644  *
 645  *      * LTTNG_UST_TP_FIELDS describes the event payload layout in the trace *
 646  *
 647  *     LTTNG_UST_TP_FIELDS(
 648  *         * Integer, printed in base 10 *
 649  *         ctf_integer(int, field_a, arg0)
 650  *
 651  *         * Integer, printed with 0x base 16 *
 652  *         ctf_integer_hex(unsigned long, field_d, arg1)
 653  *
 654  *         * Enumeration *
 655  *         ctf_enum(someproject_component, enum_name, int, field_e, arg0)
 656  *
 657  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 658  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 659  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 660  *
 661  *         * String, printed as UTF8-encoded string *
 662  *         ctf_string(field_e, string)
 663  *
 664  *         * Array sequence of signed integer values *
 665  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 666  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 667  *     )
 668  * )
 669  *
 670  * More detailed explanation:
 671  *
 672  * The name of the tracepoint is expressed as a tuple with the provider
 673  * and name arguments.
 674  *
 675  * The provider and name should be a proper C99 identifier.
 676  * The "provider" and "name" MUST follow these rules to ensure no
 677  * namespace clash occurs:
 678  *
 679  * For projects (applications and libraries) for which an entity
 680  * specific to the project controls the source code and thus its
 681  * tracepoints (typically with a scope larger than a single company):
 682  *
 683  * either:
 684  *   project_component, event
 685  * or:
 686  *   project, event
 687  *
 688  * Where "project" is the name of the project,
 689  *       "component" is the name of the project component (which may
 690  *       include several levels of sub-components, e.g.
 691  *       ...component_subcomponent_...) where the tracepoint is located
 692  *       (optional),
 693  *       "event" is the name of the tracepoint event.
 694  *
 695  * For projects issued from a single company wishing to advertise that
 696  * the company controls the source code and thus the tracepoints, the
 697  * "com_" prefix should be used:
 698  *
 699  * either:
 700  *   com_company_project_component, event
 701  * or:
 702  *   com_company_project, event
 703  *
 704  * Where "company" is the name of the company,
 705  *       "project" is the name of the project,
 706  *       "component" is the name of the project component (which may
 707  *       include several levels of sub-components, e.g.
 708  *       ...component_subcomponent_...) where the tracepoint is located
 709  *       (optional),
 710  *       "event" is the name of the tracepoint event.
 711  *
 712  * the provider:event identifier is limited to 127 characters.
 713  */
 714
 715 #define LTTNG_UST_TRACEPOINT_EVENT(provider, name, args, fields)                        \
 716         LTTNG_UST__DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))         \
 717         LTTNG_UST__DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 718
 719 #define LTTNG_UST_TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 720
 721 #define LTTNG_UST_TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)    \
 722         LTTNG_UST__DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))         \
 723         LTTNG_UST__DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 724
 725 #if LTTNG_UST_COMPAT_API(0)
 726 #define TRACEPOINT_EVENT                LTTNG_UST_TRACEPOINT_EVENT
 727 #define TRACEPOINT_EVENT_CLASS          LTTNG_UST_TRACEPOINT_EVENT_CLASS
 728 #define TRACEPOINT_EVENT_INSTANCE       LTTNG_UST_TRACEPOINT_EVENT_INSTANCE
 729 #endif /* #if LTTNG_UST_COMPAT_API(0) */
 730
 731 #endif /* #ifndef LTTNG_UST_TRACEPOINT_EVENT */
 732
 733 #ifndef TRACEPOINT_LOGLEVEL
 734
 735 /*
 736  * Tracepoint Loglevels
 737  *
 738  * Typical use of these loglevels:
 739  *
 740  * The loglevels go from 0 to 14. Higher numbers imply the most
 741  * verbosity (higher event throughput expected.
 742  *
 743  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 744  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 745  * debug information.
 746  *
 747  * TRACE_EMERG           0
 748  * system is unusable
 749  *
 750  * TRACE_ALERT           1
 751  * action must be taken immediately
 752  *
 753  * TRACE_CRIT            2
 754  * critical conditions
 755  *
 756  * TRACE_ERR             3
 757  * error conditions
 758  *
 759  * TRACE_WARNING         4
 760  * warning conditions
 761  *
 762  * TRACE_NOTICE          5
 763  * normal, but significant, condition
 764  *
 765  * TRACE_INFO            6
 766  * informational message
 767  *
 768  * TRACE_DEBUG_SYSTEM    7
 769  * debug information with system-level scope (set of programs)
 770  *
 771  * TRACE_DEBUG_PROGRAM   8
 772  * debug information with program-level scope (set of processes)
 773  *
 774  * TRACE_DEBUG_PROCESS   9
 775  * debug information with process-level scope (set of modules)
 776  *
 777  * TRACE_DEBUG_MODULE    10
 778  * debug information with module (executable/library) scope (set of units)
 779  *
 780  * TRACE_DEBUG_UNIT      11
 781  * debug information with compilation unit scope (set of functions)
 782  *
 783  * TRACE_DEBUG_FUNCTION  12
 784  * debug information with function-level scope
 785  *
 786  * TRACE_DEBUG_LINE      13
 787  * debug information with line-level scope (LTTNG_UST_TRACEPOINT_EVENT default)
 788  *
 789  * TRACE_DEBUG           14
 790  * debug-level message
 791  *
 792  * Declare tracepoint loglevels for tracepoints. A LTTNG_UST_TRACEPOINT_EVENT
 793  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 794  * tracepoint name. The first field is the provider name, the second
 795  * field is the name of the tracepoint, the third field is the loglevel
 796  * name.
 797  *
 798  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 799  *              < loglevel_name >)
 800  *
 801  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 802  * TRACEPOINT_LOGLEVEL.
 803  */
 804
 805 enum {
 806         TRACE_EMERG             = 0,
 807         TRACE_ALERT             = 1,
 808         TRACE_CRIT              = 2,
 809         TRACE_ERR               = 3,
 810         TRACE_WARNING           = 4,
 811         TRACE_NOTICE            = 5,
 812         TRACE_INFO              = 6,
 813         TRACE_DEBUG_SYSTEM      = 7,
 814         TRACE_DEBUG_PROGRAM     = 8,
 815         TRACE_DEBUG_PROCESS     = 9,
 816         TRACE_DEBUG_MODULE      = 10,
 817         TRACE_DEBUG_UNIT        = 11,
 818         TRACE_DEBUG_FUNCTION    = 12,
 819         TRACE_DEBUG_LINE        = 13,
 820         TRACE_DEBUG             = 14,
 821 };
 822
 823 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 824
 825 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 826
 827 #ifndef TRACEPOINT_MODEL_EMF_URI
 828
 829 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 830
 831 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */