src/stdlib/sharedlib.c

   1
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include "sharedlib.h"
   6
   7 #if defined(SHAREDLIB_ISWINNT)
   8 #   include <windows.h>
   9 #elif defined(SHAREDLIB_ISUNIX)
  10 #   include <unistd.h>
  11 #   include <dlfcn.h>
  12 #   include <errno.h>
  13 #endif
  14
  15 struct shl_handle_t {
  16 #ifdef SHAREDLIB_ISWINNT
  17     /* technically, HANDLE is just typedef'd to 'const void*' anyway */
  18     HANDLE libhandle;
  19 #elif defined(SHAREDLIB_ISUNIX)
  20     void* libhandle;
  21 #endif
  22     /* currently not really used */
  23     int isloaded;
  24 };
  25
  26 shl_handle_t* shl_new()
  27 {
  28     shl_handle_t* ret;
  29     ret = (shl_handle_t*)malloc(sizeof(shl_handle_t));
  30     ret->libhandle = NULL;
  31     ret->isloaded = 0;
  32     return ret;
  33 }
  34
  35 shl_handle_t* shl_openlib(const char* path)
  36 {
  37     shl_handle_t* ret;
  38     ret = shl_new();
  39 #if defined(SHAREDLIB_ISWINNT)
  40     ret->libhandle = LoadLibrary(path);
  41 #elif defined(SHAREDLIB_ISUNIX)
  42     ret->libhandle = dlopen(path, RTLD_LAZY);
  43 #endif
  44     if(ret->libhandle == NULL)
  45     {
  46         shl_destroy(ret);
  47         return NULL;
  48     }
  49     return ret;
  50 }
  51
  52 shl_handle_t* shl_openself()
  53 {
  54     shl_handle_t* ret;
  55     ret = shl_new();
  56 #if defined(SHAREDLIB_ISWINNT)
  57     HANDLE this_process;
  58     /* GetModuleHandleEx(0,0, &this_process); */
  59     this_process = GetModuleHandle(0);
  60     ret->libhandle = this_process;
  61 #elif defined(SHAREDLIB_ISUNIX)
  62     ret->libhandle = dlopen(NULL, 0);
  63 #endif
  64     return ret;
  65 }
  66
  67
  68 void shl_destroy(shl_handle_t* shl)
  69 {
  70     if(shl != NULL)
  71     {
  72         free(shl);
  73         shl = NULL;
  74     }
  75 }
  76
  77 void shl_closelib(shl_handle_t* shl)
  78 {
  79     if(shl != NULL)
  80     {
  81 #if defined(SHAREDLIB_ISWINNT)
  82         FreeLibrary(shl->libhandle);
  83 #elif defined(SHAREDLIB_ISUNIX)
  84         dlclose(shl->libhandle);
  85 #endif
  86     }
  87     shl_destroy(shl);
  88 }
  89
  90 int shl_havesym(shl_handle_t* shl, const char* sym)
  91 {
  92     if(shl_resolve(shl, sym) == NULL)
  93     {
  94         return 0;
  95     }
  96     return 1;
  97 }
  98
  99 void* shl_resolve(shl_handle_t* shl, const char* sym)
 100 {
 101     void* symaddr;
 102 #if defined(SHAREDLIB_ISWINNT)
 103     symaddr = (void*)GetProcAddress(shl->libhandle, sym);
 104 #elif defined(SHAREDLIB_ISUNIX)
 105     symaddr = (void*)dlsym(shl->libhandle, sym);
 106 #endif
 107     return symaddr;
 108 }
 109
 110 void* shl_loadsym(shl_handle_t* shl, const char* sym)
 111 {
 112     if(shl_havesym(shl, sym) == 0)
 113     {
 114         return NULL;
 115     }
 116     return shl_resolve(shl, sym);
 117 }
 118
 119 int shl_geterrcode(shl_handle_t* shl)
 120 {
 121     (void)shl;
 122 #if defined(SHAREDLIB_ISWINNT)
 123     /* the interface for loading/unloading shared objects on
 124        windows uses the global errorcode system */
 125     return GetLastError();
 126 #elif defined(SHAREDLIB_ISUNIX)
 127     return errno;
 128 #endif
 129 }
 130
 131 const char* shl_geterrstr(shl_handle_t* shl)
 132 {
 133 #if defined(SHAREDLIB_ISWINNT)
 134     int errval = shl_geterrcode(shl);
 135     /*
 136         sometimes, in localized versions of Windows XP (and newer),
 137         the output returned by FormatMessage() contains "\r\n" ...
 138         so far I have not found a 'sane' way to fix this.
 139         also, it's not like i'm the one who should fix this in the first place.
 140         YES MICROSOFT I AM TALKING ABOUT YOU FIX YOUR SHIT FOR FUCKS SAKE
 141     */
 142     LPCSTR tempmessage;
 143     FormatMessage(
 144             FORMAT_MESSAGE_FROM_SYSTEM |
 145             FORMAT_MESSAGE_ALLOCATE_BUFFER |
 146             FORMAT_MESSAGE_IGNORE_INSERTS,
 147         NULL, errval, MAKELANGID(LANG_NEUTRAL,SUBLANG_DEFAULT),
 148         (LPTSTR)& tempmessage, 0,NULL);
 149     return tempmessage;
 150 #elif defined(SHAREDLIB_ISUNIX)
 151     const char* errstr;
 152     /* sometimes dlerror() returns NULL, and in that case,
 153        we just use strerror() instead */
 154     if((errstr = dlerror()) == NULL)
 155     {
 156         errstr = strerror(shl_geterrcode(shl));
 157     }
 158     return errstr;
 159 #endif
 160 }
 161
 162 int shl_preload(const char* path)
 163 {
 164     shl_handle_t* handle;
 165     if((handle = shl_openlib(path)) == NULL)
 166     {
 167         return 0;
 168     }
 169     shl_closelib(handle);
 170     return 1;
 171
 172 }