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 }