include/lttng/tracepoint.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #ifndef _LTTNG_TRACEPOINT_H
   8 #define _LTTNG_TRACEPOINT_H
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <lttng/tracepoint-types.h>
  13 #include <lttng/tracepoint-rcu.h>
  14 #include <urcu/compiler.h>
  15 #include <urcu/system.h>
  16 #include <dlfcn.h>      /* for dlopen */
  17 #include <string.h>     /* for memset */
  18
  19 #include <lttng/ust-config.h>   /* for sdt */
  20 #include <lttng/ust-compiler.h>
  21 #include <lttng/ust-tracer.h>
  22
  23 #define LTTNG_UST_TRACEPOINT_NAME_LEN_MAX       256
  24
  25 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  26 /*
  27  * Instead of using SDT_USE_VARIADIC from 'sys/sdt.h', use our own namespaced
  28  * macros since the instrumented application might already have included
  29  * 'sys/sdt.h' without variadic support.
  30  */
  31 #include <sys/sdt.h>
  32
  33 #define _LTTNG_UST_SDT_NARG(...) \
  34         __LTTNG_UST_SDT_NARG(__VA_ARGS__, 12,11,10,9,8,7,6,5,4,3,2,1,0)
  35
  36 #define __LTTNG_UST_SDT_NARG(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12, N, ...) N
  37
  38 #define _LTTNG_UST_SDT_PROBE_N(provider, name, N, ...) \
  39         _SDT_PROBE(provider, name, N, (__VA_ARGS__))
  40
  41 #define LTTNG_UST_STAP_PROBEV(provider, name, ...) \
  42         _LTTNG_UST_SDT_PROBE_N(provider, name, _LTTNG_UST_SDT_NARG(0, ##__VA_ARGS__), ##__VA_ARGS__)
  43
  44 #else
  45 #define LTTNG_UST_STAP_PROBEV(...)
  46 #endif
  47
  48 #ifdef __cplusplus
  49 extern "C" {
  50 #endif
  51
  52 #define tracepoint_enabled(provider, name) \
  53         caa_unlikely(CMM_LOAD_SHARED(__tracepoint_##provider##___##name.state))
  54
  55 #define do_tracepoint(provider, name, ...) \
  56         __tracepoint_cb_##provider##___##name(__VA_ARGS__)
  57
  58 #define tracepoint(provider, name, ...)                                     \
  59         do {                                                                \
  60                 LTTNG_UST_STAP_PROBEV(provider, name, ## __VA_ARGS__);      \
  61                 if (tracepoint_enabled(provider, name))                     \
  62                         do_tracepoint(provider, name, __VA_ARGS__);         \
  63         } while (0)
  64
  65 #define TP_ARGS(...)       __VA_ARGS__
  66
  67 /*
  68  * TP_ARGS takes tuples of type, argument separated by a comma.
  69  * It can take up to 10 tuples (which means that less than 10 tuples is
  70  * fine too).
  71  * Each tuple is also separated by a comma.
  72  */
  73 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  74                 _tokena##_tokenb
  75 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  76                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  77 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  78                 _tokena##_tokenb##_tokenc
  79 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  80                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  81 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  82                 _tokena##_tokenb##_tokenc##_tokend
  83 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  84                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  85
  86 /*
  87  * _TP_EXVAR* extract the var names.
  88  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  89  */
  90 #define _TP_EXVAR0()
  91 #define _TP_EXVAR1(a)
  92 #define _TP_EXVAR2(a,b)                                         b
  93 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  94 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  95 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  96 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  97 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  98 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  99 #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
 100 #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
 101 #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
 102
 103 #define _TP_EXDATA_VAR0()                                               __tp_data
 104 #define _TP_EXDATA_VAR1(a)                                              __tp_data
 105 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
 106 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
 107 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
 108 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
 109 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
 110 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
 111 #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
 112 #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
 113 #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
 114 #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
 115
 116 /*
 117  * _TP_EXPROTO* extract tuples of type, var.
 118  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 119  */
 120 #define _TP_EXPROTO0()                                          void
 121 #define _TP_EXPROTO1(a)                                         void
 122 #define _TP_EXPROTO2(a,b)                                       a b
 123 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 124 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 125 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 126 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 127 #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
 128 #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
 129 #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
 130 #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
 131 #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
 132
 133 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 134 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 135 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 136 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 137 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 138 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 139 #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
 140 #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
 141 #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
 142 #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
 143 #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
 144 #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
 145
 146 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 147 #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)
 148 #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
 149 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 150 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 151 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 152 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 153 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 154 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 155 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 156 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 157 #define _TP_PARAMS(...)                 __VA_ARGS__
 158
 159 /*
 160  * sizeof(#_provider) - 1 : length of the provider string (excluding \0).
 161  * sizeof(#_name) - 1     : length of the name string (excluding \0).
 162  * + 1                    : separator between provider and event name.
 163  *
 164  * Upper bound (inclusive) is LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1 to
 165  * account for \0.
 166  *
 167  * The comparison is:
 168  *   left hand side:   sizeof(#_provider) - 1 + sizeof(#_name) - 1 + 1
 169  *   right hand side:  LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1
 170  *   operator:         <=  (inclusive)
 171  * Simplified in the code below.
 172  */
 173 #define lttng_ust_tracepoint_validate_name_len(_provider, _name)                                                \
 174         lttng_ust_static_assert(sizeof(#_provider) + sizeof(#_name) <= LTTNG_UST_TRACEPOINT_NAME_LEN_MAX,       \
 175                 "Tracepoint name length is too long",                                                           \
 176                 Tracepoint_name_length_is_too_long)
 177
 178 /*
 179  * The tracepoint cb is marked always inline so we can distinguish
 180  * between caller's ip addresses within the probe using the return
 181  * address.
 182  */
 183 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 184 extern struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name;                \
 185 static inline                                                                           \
 186 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 187         __attribute__((always_inline, unused)) lttng_ust_notrace;                       \
 188 static                                                                                  \
 189 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 190 {                                                                                       \
 191         struct lttng_ust_tracepoint_probe *__tp_probe;                                  \
 192                                                                                         \
 193         if (caa_unlikely(!TP_RCU_LINK_TEST()))                                          \
 194                 return;                                                                 \
 195         tp_rcu_read_lock();                                                             \
 196         __tp_probe = tp_rcu_dereference(__tracepoint_##_provider##___##_name.probes);   \
 197         if (caa_unlikely(!__tp_probe))                                                  \
 198                 goto end;                                                               \
 199         do {                                                                            \
 200                 void (*__tp_cb)(void) = __tp_probe->func;                               \
 201                 void *__tp_data = __tp_probe->data;                                     \
 202                                                                                         \
 203                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 204                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 205         } while ((++__tp_probe)->func);                                                 \
 206 end:                                                                                    \
 207         tp_rcu_read_unlock();                                                           \
 208 }                                                                                       \
 209 static inline                                                                           \
 210 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 211                 void (*func)(void), void *data)                                         \
 212         lttng_ust_notrace;                                                              \
 213 static inline                                                                           \
 214 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 215                 void (*func)(void), void *data)                                         \
 216 {                                                                                       \
 217         __tracepoint_probe_register(name, func, data,                                   \
 218                 __tracepoint_##_provider##___##_name.signature);                        \
 219 }                                                                                       \
 220 static inline                                                                           \
 221 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 222                 void (*func)(void), void *data)                                         \
 223         lttng_ust_notrace;                                                              \
 224 static inline                                                                           \
 225 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 226                 void (*func)(void), void *data)                                         \
 227 {                                                                                       \
 228         __tracepoint_probe_unregister(name, func, data);                                \
 229 }
 230
 231 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 232                 void *data, const char *signature);
 233 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 234                 void *data);
 235
 236 /*
 237  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 238  * shared across objects in a module/main executable.
 239  *
 240  * IMPORTANT: this structure is part of the ABI between instrumented
 241  * applications and UST. Fields need to be only added at the end, never
 242  * reordered, never removed.
 243  *
 244  * The field @struct_size should be used to determine the size of the
 245  * structure. It should be queried before using additional fields added
 246  * at the end of the structure.
 247  */
 248 struct lttng_ust_tracepoint_dlopen {
 249         uint32_t struct_size;
 250
 251         void *liblttngust_handle;
 252
 253         int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
 254                 int tracepoints_count);
 255         int (*tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
 256         void (*rcu_read_lock_sym)(void);
 257         void (*rcu_read_unlock_sym)(void);
 258         void *(*rcu_dereference_sym)(void *p);
 259
 260         /* End of base ABI. Fields below should be used after checking struct_size. */
 261 };
 262
 263 extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen;
 264 extern struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr;
 265
 266 /*
 267  * These weak symbols, the constructor, and destructor take care of
 268  * registering only _one_ instance of the tracepoints per shared-ojbect
 269  * (or for the whole main program).
 270  */
 271 int __tracepoint_registered
 272         __attribute__((weak, visibility("hidden")));
 273 int __tracepoint_ptrs_registered
 274         __attribute__((weak, visibility("hidden")));
 275 struct lttng_ust_tracepoint_dlopen tracepoint_dlopen
 276                 __attribute__((weak, visibility("hidden"))) = {
 277         .struct_size = sizeof(struct lttng_ust_tracepoint_dlopen),
 278 };
 279 /*
 280  * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc
 281  * 4.8 and prior does not have the same behavior for symbol scoping on
 282  * 32-bit powerpc depending on the object size: symbols for objects of 8
 283  * bytes or less have the same address throughout a module, whereas they
 284  * have different addresses between compile units for objects larger
 285  * than 8 bytes. Add this pointer indirection to ensure that the symbol
 286  * scoping match that of the other weak hidden symbols found in this
 287  * header.
 288  */
 289 struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr
 290         __attribute__((weak, visibility("hidden")));
 291
 292 /*
 293  * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared
 294  * across objects in a module/main executable. The callbacks are used to
 295  * control and check if the destructors should be executed.
 296  *
 297  * IMPORTANT: this structure is part of the ABI between instrumented
 298  * applications and UST. Fields need to be only added at the end, never
 299  * reordered, never removed.
 300  *
 301  * The field @struct_size should be used to determine the size of the
 302  * structure. It should be queried before using additional fields added
 303  * at the end of the structure.
 304  */
 305 struct lttng_ust_tracepoint_destructors_syms {
 306         uint32_t struct_size;
 307
 308         void (*tracepoint_disable_destructors)(void);
 309         int (*tracepoint_get_destructors_state)(void);
 310
 311         /* End of base ABI. Fields below should be used after checking struct_size. */
 312 };
 313
 314 extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms;
 315 extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr;
 316
 317 struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms
 318         __attribute__((weak, visibility("hidden"))) = {
 319         .struct_size = sizeof(struct lttng_ust_tracepoint_destructors_syms),
 320 };
 321 struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr
 322         __attribute__((weak, visibility("hidden")));
 323
 324 static inline void tracepoint_disable_destructors(void)
 325 {
 326         if (!tracepoint_dlopen_ptr)
 327                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 328         if (!tracepoint_destructors_syms_ptr)
 329                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 330         if (tracepoint_dlopen_ptr->liblttngust_handle
 331                         && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors)
 332                 tracepoint_destructors_syms_ptr->tracepoint_disable_destructors();
 333 }
 334
 335 #ifndef _LGPL_SOURCE
 336 static inline void
 337 __tracepoint__init_urcu_sym(void)
 338         lttng_ust_notrace;
 339 static inline void
 340 __tracepoint__init_urcu_sym(void)
 341 {
 342         if (!tracepoint_dlopen_ptr)
 343                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 344         /*
 345          * Symbols below are needed by tracepoint call sites and probe
 346          * providers.
 347          */
 348         if (!tracepoint_dlopen_ptr->rcu_read_lock_sym)
 349                 tracepoint_dlopen_ptr->rcu_read_lock_sym =
 350                         URCU_FORCE_CAST(void (*)(void),
 351                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 352                                         "tp_rcu_read_lock"));
 353         if (!tracepoint_dlopen_ptr->rcu_read_unlock_sym)
 354                 tracepoint_dlopen_ptr->rcu_read_unlock_sym =
 355                         URCU_FORCE_CAST(void (*)(void),
 356                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 357                                         "tp_rcu_read_unlock"));
 358         if (!tracepoint_dlopen_ptr->rcu_dereference_sym)
 359                 tracepoint_dlopen_ptr->rcu_dereference_sym =
 360                         URCU_FORCE_CAST(void *(*)(void *p),
 361                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 362                                         "tp_rcu_dereference_sym"));
 363 }
 364 #else
 365 static inline void
 366 __tracepoint__init_urcu_sym(void)
 367         lttng_ust_notrace;
 368 static inline void
 369 __tracepoint__init_urcu_sym(void)
 370 {
 371 }
 372 #endif
 373
 374 static void
 375 __tracepoints__init(void)
 376         lttng_ust_notrace __attribute__((constructor));
 377 static void
 378 __tracepoints__init(void)
 379 {
 380         if (__tracepoint_registered++) {
 381                 if (!tracepoint_dlopen_ptr->liblttngust_handle)
 382                         return;
 383                 __tracepoint__init_urcu_sym();
 384                 return;
 385         }
 386
 387         if (!tracepoint_dlopen_ptr)
 388                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 389         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 390                 tracepoint_dlopen_ptr->liblttngust_handle =
 391                         dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
 392         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 393                 return;
 394         __tracepoint__init_urcu_sym();
 395 }
 396
 397 static void
 398 __tracepoints__destroy(void)
 399         lttng_ust_notrace __attribute__((destructor));
 400 static void
 401 __tracepoints__destroy(void)
 402 {
 403         int ret;
 404
 405         if (--__tracepoint_registered)
 406                 return;
 407         if (!tracepoint_dlopen_ptr)
 408                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 409         if (!tracepoint_destructors_syms_ptr)
 410                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 411         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 412                 return;
 413         if (__tracepoint_ptrs_registered)
 414                 return;
 415         /*
 416          * Lookup if destructors must be executed using the new method.
 417          */
 418         if (tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 419                 && !tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()) {
 420                 /*
 421                  * The tracepoint_get_destructors_state symbol was found with
 422                  * dlsym but its returned value is 0 meaning that destructors
 423                  * must not be executed.
 424                  */
 425                 return;
 426         }
 427         ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 428         if (ret) {
 429                 fprintf(stderr, "Error (%d) in dlclose\n", ret);
 430                 abort();
 431         }
 432         memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 433 }
 434
 435 #ifdef TRACEPOINT_DEFINE
 436
 437 /*
 438  * These weak symbols, the constructor, and destructor take care of
 439  * registering only _one_ instance of the tracepoints per shared-ojbect
 440  * (or for the whole main program).
 441  */
 442 extern struct lttng_ust_tracepoint * const __start___tracepoints_ptrs[]
 443         __attribute__((weak, visibility("hidden")));
 444 extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[]
 445         __attribute__((weak, visibility("hidden")));
 446
 447 /*
 448  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 449  * unresolved symbol that requires the provider to be linked in. When
 450  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 451  * unresolved symbol that depends on having the provider linked in,
 452  * otherwise the linker complains. This deals with use of static
 453  * libraries, ensuring that the linker does not remove the provider
 454  * object from the executable.
 455  */
 456 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 457 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 458 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 459 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 460 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 461
 462 /*
 463  * Note: to allow PIC code, we need to allow the linker to update the pointers
 464  * in the __tracepoints_ptrs section.
 465  * Therefore, this section is _not_ const (read-only).
 466  */
 467 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 468
 469 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 470         lttng_ust_tracepoint_validate_name_len(_provider, _name);               \
 471         extern int __tracepoint_provider_##_provider;                           \
 472         static const char __tp_strtab_##_provider##___##_name[]                 \
 473                 __attribute__((section("__tracepoints_strings"))) =             \
 474                         #_provider ":" #_name;                                  \
 475         struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name        \
 476                 __attribute__((section("__tracepoints"))) = {                   \
 477                         sizeof(struct lttng_ust_tracepoint),                    \
 478                         __tp_strtab_##_provider##___##_name,                    \
 479                         0,                                                      \
 480                         NULL,                                                   \
 481                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 482                         _TP_EXTRACT_STRING(_args),                              \
 483                 };                                                              \
 484         static struct lttng_ust_tracepoint *                                    \
 485                 __tracepoint_ptr_##_provider##___##_name                        \
 486                 __attribute__((section("__tracepoints_ptrs"), used))            \
 487                 __lttng_ust_variable_attribute_no_sanitize_address =            \
 488                         &__tracepoint_##_provider##___##_name;
 489
 490 static void
 491 __tracepoints__ptrs_init(void)
 492         lttng_ust_notrace __attribute__((constructor));
 493 static void
 494 __tracepoints__ptrs_init(void)
 495 {
 496         if (__tracepoint_ptrs_registered++)
 497                 return;
 498         if (!tracepoint_dlopen_ptr)
 499                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 500         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 501                 tracepoint_dlopen_ptr->liblttngust_handle =
 502                         dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
 503         if (!tracepoint_dlopen_ptr->liblttngust_handle)
 504                 return;
 505         if (!tracepoint_destructors_syms_ptr)
 506                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 507         tracepoint_dlopen_ptr->tracepoint_register_lib =
 508                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
 509                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 510                                         "tracepoint_register_lib"));
 511         tracepoint_dlopen_ptr->tracepoint_unregister_lib =
 512                 URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
 513                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 514                                         "tracepoint_unregister_lib"));
 515         tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
 516                 URCU_FORCE_CAST(void (*)(void),
 517                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 518                                         "tp_disable_destructors"));
 519         tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state =
 520                 URCU_FORCE_CAST(int (*)(void),
 521                                 dlsym(tracepoint_dlopen_ptr->liblttngust_handle,
 522                                         "tp_get_destructors_state"));
 523         __tracepoint__init_urcu_sym();
 524         if (tracepoint_dlopen_ptr->tracepoint_register_lib) {
 525                 tracepoint_dlopen_ptr->tracepoint_register_lib(__start___tracepoints_ptrs,
 526                                 __stop___tracepoints_ptrs -
 527                                 __start___tracepoints_ptrs);
 528         }
 529 }
 530
 531 static void
 532 __tracepoints__ptrs_destroy(void)
 533         lttng_ust_notrace __attribute__((destructor));
 534 static void
 535 __tracepoints__ptrs_destroy(void)
 536 {
 537         int ret;
 538
 539         if (--__tracepoint_ptrs_registered)
 540                 return;
 541         if (!tracepoint_dlopen_ptr)
 542                 tracepoint_dlopen_ptr = &tracepoint_dlopen;
 543         if (!tracepoint_destructors_syms_ptr)
 544                 tracepoint_destructors_syms_ptr = &tracepoint_destructors_syms;
 545         if (tracepoint_dlopen_ptr->tracepoint_unregister_lib)
 546                 tracepoint_dlopen_ptr->tracepoint_unregister_lib(__start___tracepoints_ptrs);
 547         if (tracepoint_dlopen_ptr->liblttngust_handle
 548                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
 549                         && tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
 550                         && !__tracepoint_ptrs_registered) {
 551                 ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle);
 552                 if (ret) {
 553                         fprintf(stderr, "Error (%d) in dlclose\n", ret);
 554                         abort();
 555                 }
 556                 memset(tracepoint_dlopen_ptr, 0, sizeof(*tracepoint_dlopen_ptr));
 557         }
 558 }
 559
 560 #else /* TRACEPOINT_DEFINE */
 561
 562 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 563
 564 #endif /* #else TRACEPOINT_DEFINE */
 565
 566 #ifdef __cplusplus
 567 }
 568 #endif
 569
 570 #endif /* _LTTNG_TRACEPOINT_H */
 571
 572 /* The following declarations must be outside re-inclusion protection. */
 573
 574 #ifndef TRACEPOINT_ENUM
 575
 576 /*
 577  * Tracepoint Enumerations
 578  *
 579  * The enumeration is a mapping between an integer, or range of integers, and
 580  * a string. It can be used to have a more compact trace in cases where the
 581  * possible values for a field are limited:
 582  *
 583  * An example:
 584  *
 585  * TRACEPOINT_ENUM(someproject_component, enumname,
 586  *      TP_ENUM_VALUES(
 587  *              ctf_enum_value("even", 0)
 588  *              ctf_enum_value("uneven", 1)
 589  *              ctf_enum_range("twoto4", 2, 4)
 590  *              ctf_enum_value("five", 5)
 591  *      )
 592  * )
 593  *
 594  * Where "someproject_component" is the name of the component this enumeration
 595  * belongs to and "enumname" identifies this enumeration. Inside the
 596  * TP_ENUM_VALUES macro is the actual mapping. Each string value can map
 597  * to either a single value with ctf_enum_value or a range of values
 598  * with ctf_enum_range.
 599  *
 600  * Enumeration ranges may overlap, but the behavior is implementation-defined,
 601  * each trace reader will handle overlapping as it wishes.
 602  *
 603  * That enumeration can then be used in a field inside the TP_FIELD macro using
 604  * the following line:
 605  *
 606  * ctf_enum(someproject_component, enumname, enumtype, enumfield, enumval)
 607  *
 608  * Where "someproject_component" and "enumname" match those in the
 609  * TRACEPOINT_ENUM, "enumtype" is a signed or unsigned integer type
 610  * backing the enumeration, "enumfield" is the name of the field and
 611  * "enumval" is the value.
 612  */
 613
 614 #define TRACEPOINT_ENUM(provider, name, values)
 615
 616 #endif /* #ifndef TRACEPOINT_ENUM */
 617
 618 #ifndef TRACEPOINT_EVENT
 619
 620 /*
 621  * How to use the TRACEPOINT_EVENT macro:
 622  *
 623  * An example:
 624  *
 625  * TRACEPOINT_EVENT(someproject_component, event_name,
 626  *
 627  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 628  *
 629  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 630  *             long *, arg4, size_t, arg4_len),
 631  *
 632  *      * TP_FIELDS describes the event payload layout in the trace *
 633  *
 634  *     TP_FIELDS(
 635  *         * Integer, printed in base 10 *
 636  *         ctf_integer(int, field_a, arg0)
 637  *
 638  *         * Integer, printed with 0x base 16 *
 639  *         ctf_integer_hex(unsigned long, field_d, arg1)
 640  *
 641  *         * Enumeration *
 642  *         ctf_enum(someproject_component, enum_name, int, field_e, arg0)
 643  *
 644  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 645  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 646  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 647  *
 648  *         * String, printed as UTF8-encoded string *
 649  *         ctf_string(field_e, string)
 650  *
 651  *         * Array sequence of signed integer values *
 652  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 653  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 654  *     )
 655  * )
 656  *
 657  * More detailed explanation:
 658  *
 659  * The name of the tracepoint is expressed as a tuple with the provider
 660  * and name arguments.
 661  *
 662  * The provider and name should be a proper C99 identifier.
 663  * The "provider" and "name" MUST follow these rules to ensure no
 664  * namespace clash occurs:
 665  *
 666  * For projects (applications and libraries) for which an entity
 667  * specific to the project controls the source code and thus its
 668  * tracepoints (typically with a scope larger than a single company):
 669  *
 670  * either:
 671  *   project_component, event
 672  * or:
 673  *   project, event
 674  *
 675  * Where "project" is the name of the project,
 676  *       "component" is the name of the project component (which may
 677  *       include several levels of sub-components, e.g.
 678  *       ...component_subcomponent_...) where the tracepoint is located
 679  *       (optional),
 680  *       "event" is the name of the tracepoint event.
 681  *
 682  * For projects issued from a single company wishing to advertise that
 683  * the company controls the source code and thus the tracepoints, the
 684  * "com_" prefix should be used:
 685  *
 686  * either:
 687  *   com_company_project_component, event
 688  * or:
 689  *   com_company_project, event
 690  *
 691  * Where "company" is the name of the company,
 692  *       "project" is the name of the project,
 693  *       "component" is the name of the project component (which may
 694  *       include several levels of sub-components, e.g.
 695  *       ...component_subcomponent_...) where the tracepoint is located
 696  *       (optional),
 697  *       "event" is the name of the tracepoint event.
 698  *
 699  * the provider:event identifier is limited to 127 characters.
 700  */
 701
 702 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 703         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 704         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 705
 706 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 707
 708 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 709         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 710         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 711
 712 #endif /* #ifndef TRACEPOINT_EVENT */
 713
 714 #ifndef TRACEPOINT_LOGLEVEL
 715
 716 /*
 717  * Tracepoint Loglevels
 718  *
 719  * Typical use of these loglevels:
 720  *
 721  * The loglevels go from 0 to 14. Higher numbers imply the most
 722  * verbosity (higher event throughput expected.
 723  *
 724  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 725  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 726  * debug information.
 727  *
 728  * TRACE_EMERG           0
 729  * system is unusable
 730  *
 731  * TRACE_ALERT           1
 732  * action must be taken immediately
 733  *
 734  * TRACE_CRIT            2
 735  * critical conditions
 736  *
 737  * TRACE_ERR             3
 738  * error conditions
 739  *
 740  * TRACE_WARNING         4
 741  * warning conditions
 742  *
 743  * TRACE_NOTICE          5
 744  * normal, but significant, condition
 745  *
 746  * TRACE_INFO            6
 747  * informational message
 748  *
 749  * TRACE_DEBUG_SYSTEM    7
 750  * debug information with system-level scope (set of programs)
 751  *
 752  * TRACE_DEBUG_PROGRAM   8
 753  * debug information with program-level scope (set of processes)
 754  *
 755  * TRACE_DEBUG_PROCESS   9
 756  * debug information with process-level scope (set of modules)
 757  *
 758  * TRACE_DEBUG_MODULE    10
 759  * debug information with module (executable/library) scope (set of units)
 760  *
 761  * TRACE_DEBUG_UNIT      11
 762  * debug information with compilation unit scope (set of functions)
 763  *
 764  * TRACE_DEBUG_FUNCTION  12
 765  * debug information with function-level scope
 766  *
 767  * TRACE_DEBUG_LINE      13
 768  * debug information with line-level scope (TRACEPOINT_EVENT default)
 769  *
 770  * TRACE_DEBUG           14
 771  * debug-level message
 772  *
 773  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 774  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 775  * tracepoint name. The first field is the provider name, the second
 776  * field is the name of the tracepoint, the third field is the loglevel
 777  * name.
 778  *
 779  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 780  *              < loglevel_name >)
 781  *
 782  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 783  * TRACEPOINT_LOGLEVEL.
 784  */
 785
 786 enum {
 787         TRACE_EMERG             = 0,
 788         TRACE_ALERT             = 1,
 789         TRACE_CRIT              = 2,
 790         TRACE_ERR               = 3,
 791         TRACE_WARNING           = 4,
 792         TRACE_NOTICE            = 5,
 793         TRACE_INFO              = 6,
 794         TRACE_DEBUG_SYSTEM      = 7,
 795         TRACE_DEBUG_PROGRAM     = 8,
 796         TRACE_DEBUG_PROCESS     = 9,
 797         TRACE_DEBUG_MODULE      = 10,
 798         TRACE_DEBUG_UNIT        = 11,
 799         TRACE_DEBUG_FUNCTION    = 12,
 800         TRACE_DEBUG_LINE        = 13,
 801         TRACE_DEBUG             = 14,
 802 };
 803
 804 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 805
 806 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 807
 808 #ifndef TRACEPOINT_MODEL_EMF_URI
 809
 810 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 811
 812 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */