src/LoadableModule.cc

   1 /*
   2  * Copyright (C) 1996-2014 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
  11 /* The original code has this constant ./configure-able.
  12  * The "#else" branches use raw dlopen interface and have not been tested.
  13  * We can remove that code if we are going to rely on libtool's ltdl in
  14  * all environments. */
  15 #define XSTD_USE_LIBLTDL 1
  16
  17 #if XSTD_USE_LIBLTDL
  18 #include "libltdl/ltdl.h" /* generated file */
  19 #else
  20 #include <dlfcn.h>
  21 #endif
  22
  23 #include "base/TextException.h"
  24 #include "LoadableModule.h"
  25
  26 // Note: We must use preprocessor instead of C ifs because if dlopen()
  27 // is seen by the static linker, the linker will complain.
  28
  29 LoadableModule::LoadableModule(const String &aName): theName(aName), theHandle(0)
  30 {
  31 #   if XSTD_USE_LIBLTDL
  32     // Initialise preloaded symbol lookup table.
  33     LTDL_SET_PRELOADED_SYMBOLS();
  34     if (lt_dlinit() != 0)
  35         throw TexcHere("internal error: cannot initialize libtool module loader");
  36 #   endif
  37 }
  38
  39 LoadableModule::~LoadableModule()
  40 {
  41     if (loaded())
  42         unload();
  43 #   if XSTD_USE_LIBLTDL
  44     assert(lt_dlexit() == 0); // XXX: replace with a warning
  45 #   endif
  46 }
  47
  48 bool LoadableModule::loaded() const
  49 {
  50     return theHandle != 0;
  51 }
  52
  53 void LoadableModule::load(int mode)
  54 {
  55     if (loaded())
  56         throw TexcHere("internal error: reusing LoadableModule object");
  57
  58     theHandle = openModule(mode);
  59
  60     if (!loaded())
  61         throw TexcHere(errorMsg());
  62 }
  63
  64 void LoadableModule::unload()
  65 {
  66     if (!loaded())
  67         throw TexcHere("internal error: unloading not loaded module");
  68
  69     if (!closeModule())
  70         throw TexcHere(errorMsg());
  71
  72     theHandle = 0;
  73 }
  74
  75 void *LoadableModule::openModule(int mode)
  76 {
  77 #   if XSTD_USE_LIBLTDL
  78     return lt_dlopen(theName.termedBuf());
  79 #   else
  80     return dlopen(theName.termedBuf(),
  81                   mode == lmNow ? RTLD_NOW : RTLD_LAZY);
  82 #   endif
  83 }
  84
  85 bool LoadableModule::closeModule()
  86 {
  87 #   if XSTD_USE_LIBLTDL
  88     // we cast to avoid including ltdl.h in LoadableModule.h
  89     return lt_dlclose(static_cast<lt_dlhandle>(theHandle)) == 0;
  90 #   else
  91     return dlclose(theHandle) == 0;
  92 #   endif
  93 }
  94
  95 const char *LoadableModule::errorMsg()
  96 {
  97 #   if XSTD_USE_LIBLTDL
  98     return lt_dlerror();
  99 #   else
 100     return dlerror();
 101 #   endif
 102 }
 103