Python/dynload_next.c

   1
   2 /* Support for dynamic loading of extension modules on Mac OS X
   3 ** All references to "NeXT" are for historical reasons.
   4 */
   5
   6 #include "Python.h"
   7 #include "importdl.h"
   8
   9 #include <mach-o/dyld.h>
  10
  11 const struct filedescr _PyImport_DynLoadFiletab[] = {
  12         {".so", "rb", C_EXTENSION},
  13         {"module.so", "rb", C_EXTENSION},
  14         {0, 0}
  15 };
  16
  17 /*
  18 ** Python modules are Mach-O MH_BUNDLE files. The best way to load these
  19 ** is each in a private namespace, so you can load, say, a module bar and a
  20 ** module foo.bar. If we load everything in the global namespace the two
  21 ** initbar() symbols will conflict.
  22 ** However, it seems some extension packages depend upon being able to access
  23 ** each others' global symbols. There seems to be no way to eat our cake and
  24 ** have it, so the USE_DYLD_GLOBAL_NAMESPACE define determines which behaviour
  25 ** you get.
  26 */
  27
  28 #ifdef USE_DYLD_GLOBAL_NAMESPACE
  29 #define LINKOPTIONS NSLINKMODULE_OPTION_BINDNOW|NSLINKMODULE_OPTION_RETURN_ON_ERROR
  30 #else
  31 #define LINKOPTIONS NSLINKMODULE_OPTION_BINDNOW| \
  32         NSLINKMODULE_OPTION_RETURN_ON_ERROR|NSLINKMODULE_OPTION_PRIVATE
  33 #endif
  34 dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
  35                                         const char *pathname, FILE *fp)
  36 {
  37         dl_funcptr p = NULL;
  38         char funcname[258];
  39         NSObjectFileImageReturnCode rc;
  40         NSObjectFileImage image;
  41         NSModule newModule;
  42         NSSymbol theSym;
  43         const char *errString;
  44         char errBuf[512];
  45
  46         PyOS_snprintf(funcname, sizeof(funcname), "_init%.200s", shortname);
  47
  48 #ifdef USE_DYLD_GLOBAL_NAMESPACE
  49         if (NSIsSymbolNameDefined(funcname)) {
  50                 theSym = NSLookupAndBindSymbol(funcname);
  51                 p = (dl_funcptr)NSAddressOfSymbol(theSym);
  52                 return p;
  53         }
  54 #endif
  55         rc = NSCreateObjectFileImageFromFile(pathname, &image);
  56         switch(rc) {
  57                 default:
  58                 case NSObjectFileImageFailure:
  59                 case NSObjectFileImageFormat:
  60                         /* for these a message is printed on stderr by dyld */
  61                         errString = "Can't create object file image";
  62                 break;
  63                 case NSObjectFileImageSuccess:
  64                         errString = NULL;
  65                         break;
  66                 case NSObjectFileImageInappropriateFile:
  67                         errString = "Inappropriate file type for dynamic loading";
  68                         break;
  69                 case NSObjectFileImageArch:
  70                         errString = "Wrong CPU type in object file";
  71                         break;
  72                 case NSObjectFileImageAccess:
  73                         errString = "Can't read object file (no access)";
  74                         break;
  75         }
  76         if (errString == NULL) {
  77                 newModule = NSLinkModule(image, pathname, LINKOPTIONS);
  78                 if (newModule == NULL) {
  79                         int errNo;
  80                         const char *fileName, *moreErrorStr;
  81                         NSLinkEditErrors c;
  82                         NSLinkEditError( &c, &errNo, &fileName, &moreErrorStr );
  83                         PyOS_snprintf(errBuf, 512, "Failure linking new module: %s: %s",
  84                                         fileName, moreErrorStr);
  85                         errString = errBuf;
  86                 }
  87         }
  88         if (errString != NULL) {
  89                 PyErr_SetString(PyExc_ImportError, errString);
  90                 return NULL;
  91         }
  92 #ifdef USE_DYLD_GLOBAL_NAMESPACE
  93         if (!NSIsSymbolNameDefined(funcname)) {
  94                 /* UnlinkModule() isn't implemented in current versions, but calling it does no harm */
  95                 /* NSUnLinkModule(newModule, FALSE); removed: causes problems for ObjC code */
  96                 PyErr_Format(PyExc_ImportError,
  97                                  "Loaded module does not contain symbol %.200s",
  98                                  funcname);
  99                 return NULL;
 100         }
 101         theSym = NSLookupAndBindSymbol(funcname);
 102 #else
 103         theSym = NSLookupSymbolInModule(newModule, funcname);
 104         if ( theSym == NULL ) {
 105                 /* NSUnLinkModule(newModule, FALSE); removed: causes problems for ObjC code */
 106                 PyErr_Format(PyExc_ImportError,
 107                                  "Loaded module does not contain symbol %.200s",
 108                                  funcname);
 109                 return NULL;
 110         }
 111 #endif
 112         p = (dl_funcptr)NSAddressOfSymbol(theSym);
 113         return p;
 114 }