hphp/util/vdso.cpp

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com)     |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #include "hphp/util/vdso.h"
  18
  19 #define _GNU_SOURCE 1
  20 #include <dlfcn.h>
  21
  22 #include <cstring>
  23
  24 namespace HPHP { namespace Util {
  25 ///////////////////////////////////////////////////////////////////////////////
  26
  27 static Vdso s_vdso;
  28
  29 Vdso::Vdso() : m_handle(nullptr), m_clock_gettime_ns(nullptr) {
  30   m_handle = dlopen("linux-vdso.so.1", RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  31   if (!m_handle) {
  32     return;
  33   }
  34
  35   m_clock_gettime_ns =
  36     (int64_t (*)(clockid_t))dlsym(m_handle, "__vdso_clock_gettime_ns");
  37   m_clock_gettime =
  38     (int (*)(clockid_t, timespec *))dlsym(m_handle, "__vdso_clock_gettime");
  39 }
  40
  41 Vdso::~Vdso() {
  42   if (m_handle) {
  43     dlclose(m_handle);
  44   }
  45 }
  46
  47 int64_t Vdso::ClockGetTimeNS(int clk_id) {
  48   return s_vdso.clockGetTimeNS(clk_id);
  49 }
  50
  51 int Vdso::ClockGetTime(int clk_id, timespec *ts) {
  52   return s_vdso.clockGetTime(clk_id, ts);
  53 }
  54
  55 ALWAYS_INLINE int64_t Vdso::clockGetTimeNS(int clk_id) {
  56   if (m_clock_gettime_ns)
  57     return m_clock_gettime_ns(clk_id);
  58   return -1;
  59 }
  60
  61 ALWAYS_INLINE int Vdso::clockGetTime(int clk_id, timespec *ts) {
  62   if (m_clock_gettime) {
  63     memset(ts, 0, sizeof(*ts));
  64     return m_clock_gettime(clk_id, ts);
  65   }
  66   return -1;
  67 }
  68
  69 ///////////////////////////////////////////////////////////////////////////////
  70 }}