src/common/testpoint/testpoint.h

   1 /*
   2  * Copyright (C) 2012 Christian Babeux <christian.babeux@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifdef NTESTPOINT
   9
  10 #define testpoint(name)
  11 #define TESTPOINT_DECL(name)
  12
  13 #else /* NTESTPOINT */
  14
  15 #include <urcu.h> /* for caa_likely/unlikely */
  16
  17 #ifdef __cplusplus
  18 extern "C" {
  19 #endif
  20
  21 extern int lttng_testpoint_activated;
  22
  23 void *lttng_testpoint_lookup(const char *name);
  24
  25 /*
  26  * Testpoint is only active if the global lttng_testpoint_activated flag is
  27  * set.
  28  * Return a non-zero error code to indicate failure.
  29  */
  30 #define testpoint(name)                         \
  31         ((caa_unlikely(lttng_testpoint_activated))      \
  32         ? __testpoint_##name##_wrapper() : 0)
  33
  34 /*
  35  * One wrapper per testpoint is generated. This is to keep track of the symbol
  36  * lookup status and the corresponding function pointer, if any.
  37  */
  38 #define _TESTPOINT_DECL(_name)                                          \
  39         static inline int __testpoint_##_name##_wrapper(void)           \
  40         {                                                               \
  41                 int ret = 0;                                            \
  42                 static int (*tp)(void);                                 \
  43                 static int found;                                       \
  44                 const char *tp_name = "__testpoint_" #_name;            \
  45                                                                         \
  46                 if (tp) {                                               \
  47                         ret = tp();                                     \
  48                 } else {                                                \
  49                         if (!found) {                                   \
  50                                 tp = (int (*)(void)) lttng_testpoint_lookup(tp_name);   \
  51                                 if (tp) {                               \
  52                                         found = 1;                      \
  53                                         ret = tp();                     \
  54                                 } else {                                \
  55                                         found = -1;                     \
  56                                 }                                       \
  57                         }                                               \
  58                 }                                                       \
  59                 return ret;                                             \
  60         }
  61
  62 /* Testpoint declaration */
  63 #define TESTPOINT_DECL(name)    \
  64         _TESTPOINT_DECL(name)
  65
  66 #ifdef __cplusplus
  67 }
  68 #endif
  69
  70 #endif /* NTESTPOINT */