src/common/testpoint/testpoint.c

   1 /*
   2  * Copyright (C) 2012 Christian Babeux <christian.babeux@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef NTESTPOINT
   9
  10 #define _LGPL_SOURCE
  11 #include <dlfcn.h>  /* for dlsym   */
  12 #include <stdlib.h> /* for getenv  */
  13 #include <string.h> /* for strncmp */
  14
  15 #include "testpoint.h"
  16
  17 /* Environment variable used to enable the testpoints facilities. */
  18 static const char *lttng_testpoint_env_var = "LTTNG_TESTPOINT_ENABLE";
  19
  20 /* Testpoint toggle flag */
  21 int lttng_testpoint_activated;
  22
  23 /*
  24  * Toggle the support for testpoints on the application startup.
  25  */
  26 static void __attribute__((constructor)) lttng_testpoint_check(void)
  27 {
  28         char *testpoint_env_val = NULL;
  29
  30         testpoint_env_val = getenv(lttng_testpoint_env_var);
  31         if (testpoint_env_val != NULL
  32                         && (strncmp(testpoint_env_val, "1", 1) == 0)) {
  33                 lttng_testpoint_activated = 1;
  34         }
  35 }
  36
  37 /*
  38  * Lookup a symbol by name.
  39  *
  40  * Return the address where the symbol is loaded or NULL if the symbol was not
  41  * found.
  42  */
  43 void *lttng_testpoint_lookup(const char *name)
  44 {
  45         if (!name) {
  46                 return NULL;
  47         }
  48
  49         return dlsym(RTLD_DEFAULT, name);
  50 }
  51
  52 #endif /* NTESTPOINT */