src/LoadableModule.cc

   1 /*
   2  * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #include "squid.h"
  10 #include "base/TextException.h"
  11 #include "libltdl/ltdl.h" /* generated file */
  12 #include "LoadableModule.h"
  13
  14 // Note: We must use preprocessor instead of C ifs because if dlopen()
  15 // is seen by the static linker, the linker will complain.
  16
  17 LoadableModule::LoadableModule(const String &aName): theName(aName), theHandle(0)
  18 {
  19     // Initialise preloaded symbol lookup table.
  20     LTDL_SET_PRELOADED_SYMBOLS();
  21     if (lt_dlinit() != 0)
  22         throw TexcHere("internal error: cannot initialize libtool module loader");
  23 }
  24
  25 LoadableModule::~LoadableModule()
  26 {
  27     if (loaded())
  28         unload();
  29     assert(lt_dlexit() == 0); // XXX: replace with a warning
  30 }
  31
  32 bool
  33 LoadableModule::loaded() const
  34 {
  35     return theHandle != 0;
  36 }
  37
  38 void
  39 LoadableModule::load(int mode)
  40 {
  41     if (loaded())
  42         throw TexcHere("internal error: reusing LoadableModule object");
  43
  44     theHandle = openModule(mode);
  45
  46     if (!loaded())
  47         throw TexcHere(errorMsg());
  48 }
  49
  50 void
  51 LoadableModule::unload()
  52 {
  53     if (!loaded())
  54         throw TexcHere("internal error: unloading not loaded module");
  55
  56     if (!closeModule())
  57         throw TexcHere(errorMsg());
  58
  59     theHandle = 0;
  60 }
  61
  62 void *
  63 LoadableModule::openModule(int mode)
  64 {
  65     return lt_dlopen(theName.termedBuf());
  66 }
  67
  68 bool
  69 LoadableModule::closeModule()
  70 {
  71     // we cast to avoid including ltdl.h in LoadableModule.h
  72     return lt_dlclose(static_cast<lt_dlhandle>(theHandle)) == 0;
  73 }
  74
  75 const char *
  76 LoadableModule::errorMsg()
  77 {
  78     return lt_dlerror();
  79 }
  80