1 #ifndef _LTTNG_TRACEPOINT_H
2 #define _LTTNG_TRACEPOINT_H
5 * Copyright (c) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 * Permission is hereby granted to use or copy this program
11 * for any purpose, provided the above notices are retained on all copies.
12 * Permission to modify the code and to distribute modified code is granted,
13 * provided the above notices are retained, and a notice that the code was
14 * modified is included with the above copyright notice.
18 #include <lttng/tracepoint-types.h>
19 #include <urcu/compiler.h>
20 #include <dlfcn.h> /* for dlopen */
26 #define tracepoint(provider, name, ...) \
28 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
29 __tracepoint_cb_##provider##___##name(__VA_ARGS__); \
32 #define TP_ARGS(...) __VA_ARGS__
35 * TP_ARGS takes tuples of type, argument separated by a comma.
36 * It can take up to 10 tuples (which means that less than 10 tuples is
38 * Each tuple is also separated by a comma.
40 #define __TP_COMBINE_TOKENS(_tokena, _tokenb) \
42 #define _TP_COMBINE_TOKENS(_tokena, _tokenb) \
43 __TP_COMBINE_TOKENS(_tokena, _tokenb)
44 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc) \
45 _tokena##_tokenb##_tokenc
46 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc) \
47 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
48 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend) \
49 _tokena##_tokenb##_tokenc##_tokend
50 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend) \
51 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
53 /* _TP_EXVAR* extract the var names. */
55 #define _TP_EXVAR2(a,b) b
56 #define _TP_EXVAR4(a,b,c,d) b,d
57 #define _TP_EXVAR6(a,b,c,d,e,f) b,d,f
58 #define _TP_EXVAR8(a,b,c,d,e,f,g,h) b,d,f,h
59 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j) b,d,f,h,j
60 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l) b,d,f,h,j,l
61 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) b,d,f,h,j,l,n
62 #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
63 #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
64 #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
66 #define _TP_EXDATA_VAR0() __tp_data
67 #define _TP_EXDATA_VAR2(a,b) __tp_data,b
68 #define _TP_EXDATA_VAR4(a,b,c,d) __tp_data,b,d
69 #define _TP_EXDATA_VAR6(a,b,c,d,e,f) __tp_data,b,d,f
70 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h) __tp_data,b,d,f,h
71 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j) __tp_data,b,d,f,h,j
72 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l) __tp_data,b,d,f,h,j,l
73 #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
74 #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
75 #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
76 #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
78 /* _TP_EXPROTO* extract tuples of type, var */
79 #define _TP_EXPROTO0()
80 #define _TP_EXPROTO2(a,b) a b
81 #define _TP_EXPROTO4(a,b,c,d) a b,c d
82 #define _TP_EXPROTO6(a,b,c,d,e,f) a b,c d,e f
83 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h) a b,c d,e f,g h
84 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j) a b,c d,e f,g h,i j
85 #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
86 #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
87 #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
88 #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
89 #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
91 #define _TP_EXDATA_PROTO0() void *__tp_data
92 #define _TP_EXDATA_PROTO2(a,b) void *__tp_data,a b
93 #define _TP_EXDATA_PROTO4(a,b,c,d) void *__tp_data,a b,c d
94 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f) void *__tp_data,a b,c d,e f
95 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h) void *__tp_data,a b,c d,e f,g h
96 #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
97 #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
98 #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
99 #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
100 #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
101 #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
103 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
104 #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)
105 #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
106 #define _TP_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
107 #define _TP_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
108 #define _TP_DATA_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
109 #define _TP_DATA_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
110 #define _TP_ARGS_PROTO(...) _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
111 #define _TP_ARGS_VAR(...) _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
112 #define _TP_ARGS_DATA_PROTO(...) _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
113 #define _TP_ARGS_DATA_VAR(...) _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
114 #define _TP_PARAMS(...) __VA_ARGS__
117 #define _TP_RCU_LINK_TEST() 1
119 #define _TP_RCU_LINK_TEST() rcu_read_lock_bp
122 #define _DECLARE_TRACEPOINT(provider, name, ...) \
123 extern struct tracepoint __tracepoint_##provider##___##name; \
124 static inline void __tracepoint_cb_##provider##___##name(_TP_ARGS_PROTO(__VA_ARGS__)) \
126 struct tracepoint_probe *__tp_probe; \
128 if (!_TP_RCU_LINK_TEST()) \
130 rcu_read_lock_bp(); \
131 __tp_probe = rcu_dereference_bp(__tracepoint_##provider##___##name.probes); \
132 if (caa_unlikely(!__tp_probe)) \
135 void *__tp_cb = __tp_probe->func; \
136 void *__tp_data = __tp_probe->data; \
138 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb) \
139 (_TP_ARGS_DATA_VAR(__VA_ARGS__)); \
140 } while ((++__tp_probe)->func); \
142 rcu_read_unlock_bp(); \
144 static inline void __tracepoint_register_##provider##___##name(char *name, \
145 void *func, void *data) \
147 __tracepoint_probe_register(name, func, data); \
149 static inline void __tracepoint_unregister_##provider##___##name(char *name, \
150 void *func, void *data) \
152 __tracepoint_probe_unregister(name, func, data); \
155 extern int __tracepoint_probe_register(const char *name
, void *func
, void *data
);
156 extern int __tracepoint_probe_unregister(const char *name
, void *func
, void *data
);
158 #ifdef TRACEPOINT_DEFINE
161 * Note: to allow PIC code, we need to allow the linker to update the pointers
162 * in the __tracepoints_ptrs section.
163 * Therefore, this section is _not_ const (read-only).
165 #define _DEFINE_TRACEPOINT(provider, name) \
166 static const char __tp_strtab_##provider##___##name[] \
167 __attribute__((section("__tracepoints_strings"))) = \
168 #provider ":" #name; \
169 struct tracepoint __tracepoint_##provider##___##name \
170 __attribute__((section("__tracepoints"))) = \
171 { __tp_strtab_##provider##___##name, 0, NULL }; \
172 static struct tracepoint * __tracepoint_ptr_##provider##___##name \
173 __attribute__((used, section("__tracepoints_ptrs"))) = \
174 &__tracepoint_##provider##___##name;
176 static int (*tracepoint_register_lib
)(struct tracepoint
* const *tracepoints_start
,
177 int tracepoints_count
);
178 static int (*tracepoint_unregister_lib
)(struct tracepoint
* const *tracepoints_start
);
179 static void *liblttngust_handle
;
182 * These weak symbols, the constructor, and destructor take care of
183 * registering only _one_ instance of the tracepoints per shared-ojbect
184 * (or for the whole main program).
186 extern struct tracepoint
* const __start___tracepoints_ptrs
[]
187 __attribute__((weak
, visibility("hidden")));
188 extern struct tracepoint
* const __stop___tracepoints_ptrs
[]
189 __attribute__((weak
, visibility("hidden")));
190 int __tracepoint_registered
191 __attribute__((weak
, visibility("hidden")));
193 static void __attribute__((constructor
)) __tracepoints__init(void)
195 if (__tracepoint_registered
++)
198 liblttngust_handle
= dlopen("liblttng-ust.so", RTLD_NOW
| RTLD_GLOBAL
);
199 if (!liblttngust_handle
)
201 tracepoint_register_lib
=
202 URCU_FORCE_CAST(int (*)(struct tracepoint
* const *, int),
203 dlsym(liblttngust_handle
,
204 "tracepoint_register_lib"));
205 tracepoint_unregister_lib
=
206 URCU_FORCE_CAST(int (*)(struct tracepoint
* const *),
207 dlsym(liblttngust_handle
,
208 "tracepoint_unregister_lib"));
209 tracepoint_register_lib(__start___tracepoints_ptrs
,
210 __stop___tracepoints_ptrs
-
211 __start___tracepoints_ptrs
);
214 static void __attribute__((destructor
)) __tracepoints__destroy(void)
217 if (--__tracepoint_registered
)
219 if (tracepoint_unregister_lib
)
220 tracepoint_unregister_lib(__start___tracepoints_ptrs
);
221 if (liblttngust_handle
) {
222 tracepoint_unregister_lib
= NULL
;
223 tracepoint_register_lib
= NULL
;
224 ret
= dlclose(liblttngust_handle
);
229 #else /* TRACEPOINT_DEFINE */
231 #define _DEFINE_TRACEPOINT(provider, name)
233 #endif /* #else TRACEPOINT_DEFINE */
239 #endif /* _LTTNG_TRACEPOINT_H */
241 /* The following declarations must be outside re-inclusion protection. */
243 #ifndef TRACEPOINT_EVENT
246 * How to use the TRACEPOINT_EVENT macro:
250 * TRACEPOINT_EVENT(someproject_component, event_name,
252 * * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
254 * TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
255 * long *, arg4, size_t, arg4_len),
257 * * TP_FIELDS describes the event payload layout in the trace *
260 * * Integer, printed in base 10 *
261 * ctf_integer(int, field_a, arg0)
263 * * Integer, printed with 0x base 16 *
264 * ctf_integer_hex(unsigned long, field_d, arg1)
266 * * Array Sequence, printed as UTF8-encoded array of bytes *
267 * ctf_array_text(char, field_b, string, FIXED_LEN)
268 * ctf_sequence_text(char, field_c, string, size_t, strlen)
270 * * String, printed as UTF8-encoded string *
271 * ctf_string(field_e, string)
273 * * Array sequence of signed integer values *
274 * ctf_array(long, field_f, arg4, FIXED_LEN4)
275 * ctf_sequence(long, field_g, arg4, size_t, arg4_len)
279 * More detailed explanation:
281 * The name of the tracepoint is expressed as a tuple with the provider
282 * and name arguments.
284 * The provider and name should be a proper C99 identifier.
285 * The "provider" and "name" MUST follow these rules to ensure no
286 * namespace clash occurs:
288 * For projects (applications and libraries) for which an entity
289 * specific to the project controls the source code and thus its
290 * tracepoints (typically with a scope larger than a single company):
293 * project_component, event
297 * Where "project" is the name of the project,
298 * "component" is the name of the project component (which may
299 * include several levels of sub-components, e.g.
300 * ...component_subcomponent_...) where the tracepoint is located
302 * "event" is the name of the tracepoint event.
304 * For projects issued from a single company wishing to advertise that
305 * the company controls the source code and thus the tracepoints, the
306 * "com_" prefix should be used:
309 * com_company_project_component, event
311 * com_company_project, event
313 * Where "company" is the name of the company,
314 * "project" is the name of the project,
315 * "component" is the name of the project component (which may
316 * include several levels of sub-components, e.g.
317 * ...component_subcomponent_...) where the tracepoint is located
319 * "event" is the name of the tracepoint event.
321 * the provider:event identifier is limited to 127 characters.
324 #define TRACEPOINT_EVENT(provider, name, args, fields) \
325 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
326 _DEFINE_TRACEPOINT(provider, name)
328 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
330 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args) \
331 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
332 _DEFINE_TRACEPOINT(provider, name)
334 #endif /* #ifndef TRACEPOINT_EVENT */
336 #ifndef TRACEPOINT_LOGLEVEL
339 * Tracepoint Loglevel Declaration Facility
341 * This is a place-holder the tracepoint loglevel declaration,
342 * overridden by the tracer implementation.
344 * Typical use of these loglevels:
346 * 1) Declare the mapping between loglevel names and an integer values
347 * within TRACEPOINT_LOGLEVEL_ENUM(), using tp_loglevel() for each
348 * tuple. Do _NOT_ add comma (,) nor semicolon (;) between the
349 * tp_loglevel entries contained within TRACEPOINT_LOGLEVEL_ENUM().
350 * Do _NOT_ add comma (,) nor semicolon (;) after the
351 * TRACEPOINT_LOGLEVEL_ENUM() declaration. The name should be a
352 * proper C99 identifier.
354 * TRACEPOINT_LOGLEVEL_ENUM(
355 * tp_loglevel( < loglevel_name >, < value > )
356 * tp_loglevel( < loglevel_name >, < value > )
362 * TRACEPOINT_LOGLEVEL_ENUM(
363 * tp_loglevel(LOG_EMERG, 0)
364 * tp_loglevel(LOG_ALERT, 1)
365 * tp_loglevel(LOG_CRIT, 2)
366 * tp_loglevel(LOG_ERR, 3)
367 * tp_loglevel(LOG_WARNING, 4)
368 * tp_loglevel(LOG_NOTICE, 5)
369 * tp_loglevel(LOG_INFO, 6)
370 * tp_loglevel(LOG_DEBUG, 7)
373 * 2) Then, declare tracepoint loglevels for tracepoints. A
374 * TRACEPOINT_EVENT should be declared prior to the the
375 * TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field
376 * is the name of the tracepoint, the second field is the loglevel
379 * TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
382 * The TRACEPOINT_PROVIDER must be defined when declaring a
383 * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint
384 * loglevel enumeration apply to the entire TRACEPOINT_PROVIDER. Only one
385 * tracepoint loglevel enumeration should be declared per tracepoint
389 #define TRACEPOINT_LOGLEVEL_ENUM(...)
390 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
392 #endif /* #ifndef TRACEPOINT_LOGLEVEL */