src/LoadableModule.cc

   1 #include "squid.h"
   2
   3 /* The original code has this constant ./configure-able.
   4  * The "#else" branches use raw dlopen interface and have not been tested.
   5  * We can remove that code if we are going to rely on libtool's ltdl in
   6  * all environments. */
   7 #define XSTD_USE_LIBLTDL 1
   8
   9 #if XSTD_USE_LIBLTDL
  10 #include "libltdl/ltdl.h" /* generated file */
  11 #else
  12 #include <dlfcn.h>
  13 #endif
  14
  15 #include "base/TextException.h"
  16 #include "LoadableModule.h"
  17
  18 // Note: We must use preprocessor instead of C ifs because if dlopen()
  19 // is seen by the static linker, the linker will complain.
  20
  21 LoadableModule::LoadableModule(const String &aName): theName(aName), theHandle(0)
  22 {
  23 #       if XSTD_USE_LIBLTDL
  24     // Initialise preloaded symbol lookup table.
  25     LTDL_SET_PRELOADED_SYMBOLS();
  26     if (lt_dlinit() != 0)
  27         throw TexcHere("internal error: cannot initialize libtool module loader");
  28 #       endif
  29 }
  30
  31 LoadableModule::~LoadableModule()
  32 {
  33     if (loaded())
  34         unload();
  35 #       if XSTD_USE_LIBLTDL
  36     assert(lt_dlexit() == 0); // XXX: replace with a warning
  37 #       endif
  38 }
  39
  40 bool LoadableModule::loaded() const
  41 {
  42     return theHandle != 0;
  43 }
  44
  45 void LoadableModule::load(int mode)
  46 {
  47     if (loaded())
  48         throw TexcHere("internal error: reusing LoadableModule object");
  49
  50     theHandle = openModule(mode);
  51
  52     if (!loaded())
  53         throw TexcHere(errorMsg());
  54 }
  55
  56 void LoadableModule::unload()
  57 {
  58     if (!loaded())
  59         throw TexcHere("internal error: unloading not loaded module");
  60
  61     if (!closeModule())
  62         throw TexcHere(errorMsg());
  63
  64     theHandle = 0;
  65 }
  66
  67 void *LoadableModule::openModule(int mode)
  68 {
  69 #       if XSTD_USE_LIBLTDL
  70     return lt_dlopen(theName.termedBuf());
  71 #       else
  72     return dlopen(theName.termedBuf(),
  73                   mode == lmNow ? RTLD_NOW : RTLD_LAZY);
  74 #       endif
  75 }
  76
  77 bool LoadableModule::closeModule()
  78 {
  79 #       if XSTD_USE_LIBLTDL
  80     // we cast to avoid including ltdl.h in LoadableModule.h
  81     return lt_dlclose(static_cast<lt_dlhandle>(theHandle)) == 0;
  82 #       else
  83     return dlclose(theHandle) == 0;
  84 #       endif
  85 }
  86
  87 const char *LoadableModule::errorMsg()
  88 {
  89 #       if XSTD_USE_LIBLTDL
  90     return lt_dlerror();
  91 #       else
  92     return dlerror();
  93 #       endif
  94 }