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 <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_TOKENS1(_tokena, _tokenb) _tokena##_tokenb
41 #define _TP_COMBINE_TOKENS(_tokena, _tokenb) _TP_COMBINE_TOKENS1(_tokena, _tokenb)
43 /* _TP_EXVAR* extract the var names. */
45 #define _TP_EXVAR2(a,b) b
46 #define _TP_EXVAR4(a,b,c,d) b,d
47 #define _TP_EXVAR6(a,b,c,d,e,f) b,d,f
48 #define _TP_EXVAR8(a,b,c,d,e,f,g,h) b,d,f,h
49 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j) b,d,f,h,j
50 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l) b,d,f,h,j,l
51 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) b,d,f,h,j,l,n
52 #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
53 #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
54 #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
56 #define _TP_EXDATA_VAR0() __tp_data
57 #define _TP_EXDATA_VAR2(a,b) __tp_data,b
58 #define _TP_EXDATA_VAR4(a,b,c,d) __tp_data,b,d
59 #define _TP_EXDATA_VAR6(a,b,c,d,e,f) __tp_data,b,d,f
60 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h) __tp_data,b,d,f,h
61 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j) __tp_data,b,d,f,h,j
62 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l) __tp_data,b,d,f,h,j,l
63 #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
64 #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
65 #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
66 #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
68 /* _TP_EXPROTO* extract tuples of type, var */
69 #define _TP_EXPROTO0()
70 #define _TP_EXPROTO2(a,b) a b
71 #define _TP_EXPROTO4(a,b,c,d) a b,c d
72 #define _TP_EXPROTO6(a,b,c,d,e,f) a b,c d,e f
73 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h) a b,c d,e f,g h
74 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j) a b,c d,e f,g h,i j
75 #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
76 #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
77 #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
78 #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
79 #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
81 #define _TP_EXDATA_PROTO0() void *__tp_data
82 #define _TP_EXDATA_PROTO2(a,b) void *__tp_data,a b
83 #define _TP_EXDATA_PROTO4(a,b,c,d) void *__tp_data,a b,c d
84 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f) void *__tp_data,a b,c d,e f
85 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h) void *__tp_data,a b,c d,e f,g h
86 #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
87 #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
88 #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
89 #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
90 #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
91 #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
93 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
94 #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)
95 #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
96 #define _TP_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
97 #define _TP_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
98 #define _TP_DATA_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
99 #define _TP_DATA_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
100 #define _TP_ARGS_PROTO(...) _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
101 #define _TP_ARGS_VAR(...) _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
102 #define _TP_ARGS_DATA_PROTO(...) _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
103 #define _TP_ARGS_DATA_VAR(...) _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
104 #define _TP_PARAMS(...) __VA_ARGS__
106 #define _DECLARE_TRACEPOINT(provider, name, ...) \
107 extern struct tracepoint __tracepoint_##provider##___##name; \
108 static inline void __tracepoint_cb_##provider##___##name(_TP_ARGS_PROTO(__VA_ARGS__)) \
110 struct tracepoint_probe *__tp_probe; \
112 if (!rcu_read_lock_bp) \
114 rcu_read_lock_bp(); \
115 __tp_probe = rcu_dereference_bp(__tracepoint_##provider##___##name.probes); \
116 if (caa_unlikely(!__tp_probe)) \
119 void *__tp_cb = __tp_probe->func; \
120 void *__tp_data = __tp_probe->data; \
122 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb) \
123 (_TP_ARGS_DATA_VAR(__VA_ARGS__)); \
124 } while ((++__tp_probe)->func); \
126 rcu_read_unlock_bp(); \
128 static inline void __tracepoint_register_##provider##___##name(char *name, \
129 void *func, void *data) \
131 __tracepoint_probe_register(name, func, data); \
133 static inline void __tracepoint_unregister_##provider##___##name(char *name, \
134 void *func, void *data) \
136 __tracepoint_probe_unregister(name, func, data); \
139 extern int __tracepoint_probe_register(const char *name
, void *func
, void *data
);
140 extern int __tracepoint_probe_unregister(const char *name
, void *func
, void *data
);
142 #ifdef TRACEPOINT_DEFINE
145 * Note: to allow PIC code, we need to allow the linker to update the pointers
146 * in the __tracepoints_ptrs section.
147 * Therefore, this section is _not_ const (read-only).
149 #define _DEFINE_TRACEPOINT(provider, name) \
150 static const char __tp_strtab_##provider##___##name[] \
151 __attribute__((section("__tracepoints_strings"))) = \
152 #provider ":" #name; \
153 struct tracepoint __tracepoint_##provider##___##name \
154 __attribute__((section("__tracepoints"))) = \
155 { __tp_strtab_##provider##___##name, 0, NULL }; \
156 static struct tracepoint * __tracepoint_ptr_##provider##___##name \
157 __attribute__((used, section("__tracepoints_ptrs"))) = \
158 &__tracepoint_##provider##___##name;
160 static int (*tracepoint_register_lib
)(struct tracepoint
* const *tracepoints_start
,
161 int tracepoints_count
);
162 static int (*tracepoint_unregister_lib
)(struct tracepoint
* const *tracepoints_start
);
163 static void *liblttngust_handle
;
166 * These weak symbols, the constructor, and destructor take care of
167 * registering only _one_ instance of the tracepoints per shared-ojbect
168 * (or for the whole main program).
170 extern struct tracepoint
* const __start___tracepoints_ptrs
[]
171 __attribute__((weak
, visibility("hidden")));
172 extern struct tracepoint
* const __stop___tracepoints_ptrs
[]
173 __attribute__((weak
, visibility("hidden")));
174 int __tracepoint_registered
175 __attribute__((weak
, visibility("hidden")));
177 static void __attribute__((constructor
)) __tracepoints__init(void)
179 if (__tracepoint_registered
++)
182 liblttngust_handle
= dlopen("liblttng-ust.so", RTLD_NOW
| RTLD_GLOBAL
);
183 if (!liblttngust_handle
)
185 tracepoint_register_lib
= dlsym(liblttngust_handle
,
186 "tracepoint_register_lib");
187 tracepoint_unregister_lib
= dlsym(liblttngust_handle
,
188 "tracepoint_unregister_lib");
189 tracepoint_register_lib(__start___tracepoints_ptrs
,
190 __stop___tracepoints_ptrs
-
191 __start___tracepoints_ptrs
);
194 static void __attribute__((destructor
)) __tracepoints__destroy(void)
197 if (--__tracepoint_registered
)
199 if (tracepoint_unregister_lib
)
200 tracepoint_unregister_lib(__start___tracepoints_ptrs
);
201 if (liblttngust_handle
) {
202 tracepoint_unregister_lib
= NULL
;
203 tracepoint_register_lib
= NULL
;
204 ret
= dlclose(liblttngust_handle
);
209 #else /* TRACEPOINT_DEFINE */
211 #define _DEFINE_TRACEPOINT(provider, name)
213 #endif /* #else TRACEPOINT_DEFINE */
219 #endif /* _LTTNG_TRACEPOINT_H */
221 /* The following declarations must be outside re-inclusion protection. */
223 #ifndef TRACEPOINT_EVENT
226 * How to use the TRACEPOINT_EVENT macro:
230 * TRACEPOINT_EVENT(someproject_component, event_name,
232 * * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
234 * TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
235 * long *, arg4, size_t, arg4_len),
237 * * TP_FIELDS describes the event payload layout in the trace *
240 * * Integer, printed in base 10 *
241 * ctf_integer(int, field_a, arg0)
243 * * Integer, printed with 0x base 16 *
244 * ctf_integer_hex(unsigned long, field_d, arg1)
246 * * Array Sequence, printed as UTF8-encoded array of bytes *
247 * ctf_array_text(char, field_b, string, FIXED_LEN)
248 * ctf_sequence_text(char, field_c, string, size_t, strlen)
250 * * String, printed as UTF8-encoded string *
251 * ctf_string(field_e, string)
253 * * Array sequence of signed integer values *
254 * ctf_array(long, field_f, arg4, FIXED_LEN4)
255 * ctf_sequence(long, field_g, arg4, size_t, arg4_len)
259 * More detailed explanation:
261 * The name of the tracepoint is expressed as a tuple with the provider
262 * and name arguments.
264 * The provider and name should be a proper C99 identifier.
265 * The "provider" and "name" MUST follow these rules to ensure no
266 * namespace clash occurs:
268 * For projects (applications and libraries) for which an entity
269 * specific to the project controls the source code and thus its
270 * tracepoints (typically with a scope larger than a single company):
273 * project_component, event
277 * Where "project" is the name of the project,
278 * "component" is the name of the project component (which may
279 * include several levels of sub-components, e.g.
280 * ...component_subcomponent_...) where the tracepoint is located
282 * "event" is the name of the tracepoint event.
284 * For projects issued from a single company wishing to advertise that
285 * the company controls the source code and thus the tracepoints, the
286 * "com_" prefix should be used:
289 * com_company_project_component, event
291 * com_company_project, event
293 * Where "company" is the name of the company,
294 * "project" is the name of the project,
295 * "component" is the name of the project component (which may
296 * include several levels of sub-components, e.g.
297 * ...component_subcomponent_...) where the tracepoint is located
299 * "event" is the name of the tracepoint event.
301 * the provider:event identifier is limited to 127 characters.
304 #define TRACEPOINT_EVENT(provider, name, args, fields) \
305 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
306 _DEFINE_TRACEPOINT(provider, name)
308 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
310 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args) \
311 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
312 _DEFINE_TRACEPOINT(provider, name)
314 #endif /* #ifndef TRACEPOINT_EVENT */
316 #ifndef TRACEPOINT_LOGLEVEL
319 * Tracepoint Loglevel Declaration Facility
321 * This is a place-holder the tracepoint loglevel declaration,
322 * overridden by the tracer implementation.
324 * Typical use of these loglevels:
326 * 1) Declare the mapping between loglevel names and an integer values
327 * within TRACEPOINT_LOGLEVEL_ENUM(), using tp_loglevel() for each
328 * tuple. Do _NOT_ add comma (,) nor semicolon (;) between the
329 * tp_loglevel entries contained within TRACEPOINT_LOGLEVEL_ENUM().
330 * Do _NOT_ add comma (,) nor semicolon (;) after the
331 * TRACEPOINT_LOGLEVEL_ENUM() declaration. The name should be a
332 * proper C99 identifier.
334 * TRACEPOINT_LOGLEVEL_ENUM(
335 * tp_loglevel( < loglevel_name >, < value > )
336 * tp_loglevel( < loglevel_name >, < value > )
342 * TRACEPOINT_LOGLEVEL_ENUM(
343 * tp_loglevel(LOG_EMERG, 0)
344 * tp_loglevel(LOG_ALERT, 1)
345 * tp_loglevel(LOG_CRIT, 2)
346 * tp_loglevel(LOG_ERR, 3)
347 * tp_loglevel(LOG_WARNING, 4)
348 * tp_loglevel(LOG_NOTICE, 5)
349 * tp_loglevel(LOG_INFO, 6)
350 * tp_loglevel(LOG_DEBUG, 7)
353 * 2) Then, declare tracepoint loglevels for tracepoints. A
354 * TRACEPOINT_EVENT should be declared prior to the the
355 * TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field
356 * is the name of the tracepoint, the second field is the loglevel
359 * TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
362 * The TRACEPOINT_PROVIDER must be defined when declaring a
363 * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint
364 * loglevel enumeration apply to the entire TRACEPOINT_PROVIDER. Only one
365 * tracepoint loglevel enumeration should be declared per tracepoint
369 #define TRACEPOINT_LOGLEVEL_ENUM(...)
370 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
372 #endif /* #ifndef TRACEPOINT_LOGLEVEL */