ceph/src/common/TracepointProvider.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #include "common/TracepointProvider.h"
   5 #include "common/config.h"
   6
   7 TracepointProvider::TracepointProvider(CephContext *cct, const char *library,
   8                                        const char *config_key)
   9   : m_cct(cct), m_library(library), m_config_keys{config_key, NULL},
  10     m_lock("TracepointProvider::m_lock") {
  11   m_cct->_conf->add_observer(this);
  12   verify_config(m_cct->_conf);
  13 }
  14
  15 TracepointProvider::~TracepointProvider() {
  16   m_cct->_conf->remove_observer(this);
  17   if (m_handle) {
  18     dlclose(m_handle);
  19   }
  20 }
  21
  22 void TracepointProvider::handle_conf_change(
  23     const struct md_config_t *conf, const std::set<std::string> &changed) {
  24   if (changed.count(m_config_keys[0])) {
  25     verify_config(conf);
  26   }
  27 }
  28
  29 void TracepointProvider::verify_config(const struct md_config_t *conf) {
  30   Mutex::Locker locker(m_lock);
  31   if (m_handle) {
  32     return;
  33   }
  34
  35   char buf[10];
  36   char *pbuf = buf;
  37   if (conf->get_val(m_config_keys[0], &pbuf, sizeof(buf)) != 0 ||
  38       strncmp(buf, "true", 5) != 0) {
  39     return;
  40   }
  41
  42   m_handle = dlopen(m_library.c_str(), RTLD_NOW | RTLD_NODELETE);
  43   assert(m_handle);
  44 }
  45