runtime/objc-load.m

   1 /*
   2  * Copyright (c) 1999-2001, 2004-2007 Apple Inc.  All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  *      objc-load.m
  26  *      Copyright 1988-1996, NeXT Software, Inc.
  27  *      Author: s. naroff
  28  *
  29  */
  30
  31 #include "objc-private.h"
  32 #include "objc-load.h"
  33
  34 #if !__OBJC2__  &&  !TARGET_OS_WIN32
  35
  36 extern void (*callbackFunction)( Class, Category );
  37
  38
  39 /**********************************************************************************
  40 * objc_loadModule.
  41 *
  42 * NOTE: Loading isn't really thread safe.  If a load message recursively calls
  43 * objc_loadModules() both sets will be loaded correctly, but if the original
  44 * caller calls objc_unloadModules() it will probably unload the wrong modules.
  45 * If a load message calls objc_unloadModules(), then it will unload
  46 * the modules currently being loaded, which will probably cause a crash.
  47 *
  48 * Error handling is still somewhat crude.  If we encounter errors while
  49 * linking up classes or categories, we will not recover correctly.
  50 *
  51 * I removed attempts to lock the class hashtable, since this introduced
  52 * deadlock which was hard to remove.  The only way you can get into trouble
  53 * is if one thread loads a module while another thread tries to access the
  54 * loaded classes (using objc_lookUpClass) before the load is complete.
  55 **********************************************************************************/
  56 int objc_loadModule(char *moduleName, void (*class_callback) (Class, Category), int *errorCode)
  57 {
  58     int                                                         successFlag = 1;
  59     int                                                         locErrorCode;
  60     NSObjectFileImage                           objectFileImage;
  61     NSObjectFileImageReturnCode         code;
  62
  63     // So we don't have to check this everywhere
  64     if (errorCode == NULL)
  65         errorCode = &locErrorCode;
  66
  67     if (moduleName == NULL)
  68     {
  69         *errorCode = NSObjectFileImageInappropriateFile;
  70         return 0;
  71     }
  72
  73     if (_dyld_present () == 0)
  74     {
  75         *errorCode = NSObjectFileImageFailure;
  76         return 0;
  77     }
  78
  79     callbackFunction = class_callback;
  80     code = NSCreateObjectFileImageFromFile (moduleName, &objectFileImage);
  81     if (code != NSObjectFileImageSuccess)
  82     {
  83         *errorCode = code;
  84         return 0;
  85     }
  86
  87     if (NSLinkModule(objectFileImage, moduleName, NSLINKMODULE_OPTION_RETURN_ON_ERROR) == NULL) {
  88         NSLinkEditErrors error;
  89         int errorNum;
  90         const char *fileName, *errorString;
  91         NSLinkEditError(&error, &errorNum, &fileName, &errorString);
  92         // These errors may overlap with other errors that objc_loadModule returns in other failure cases.
  93         *errorCode = error;
  94         return 0;
  95     }
  96     callbackFunction = NULL;
  97
  98
  99     return successFlag;
 100 }
 101
 102 /**********************************************************************************
 103 * objc_loadModules.
 104 **********************************************************************************/
 105 /* Lock for dynamic loading and unloading. */
 106 //      static OBJC_DECLARE_LOCK (loadLock);
 107
 108
 109 long    objc_loadModules   (char *                      modlist[],
 110                          void *                 errStream,
 111                          void                   (*class_callback) (Class, Category),
 112                          headerType **  hdr_addr,
 113                          char *                 debug_file)
 114 {
 115     char **                             modules;
 116     int                                 code;
 117     int                                 itWorked;
 118
 119     if (modlist == 0)
 120         return 0;
 121
 122     for (modules = &modlist[0]; *modules != 0; modules++)
 123     {
 124         itWorked = objc_loadModule (*modules, class_callback, &code);
 125         if (itWorked == 0)
 126         {
 127             //if (errStream)
 128             //  NXPrintf ((NXStream *) errStream, "objc_loadModules(%s) code = %d\n", *modules, code);
 129             return 1;
 130         }
 131
 132         if (hdr_addr)
 133             *(hdr_addr++) = 0;
 134     }
 135
 136     return 0;
 137 }
 138
 139 /**********************************************************************************
 140 * objc_unloadModules.
 141 *
 142 * NOTE:  Unloading isn't really thread safe.  If an unload message calls
 143 * objc_loadModules() or objc_unloadModules(), then the current call
 144 * to objc_unloadModules() will probably unload the wrong stuff.
 145 **********************************************************************************/
 146
 147 long    objc_unloadModules (void *                      errStream,
 148                          void                   (*unload_callback) (Class, Category))
 149 {
 150     headerType *        header_addr = 0;
 151     int errflag = 0;
 152
 153     // TODO: to make unloading work, should get the current header
 154
 155     if (header_addr)
 156     {
 157         ; // TODO: unload the current header
 158     }
 159     else
 160     {
 161         errflag = 1;
 162     }
 163
 164     return errflag;
 165 }
 166
 167 #endif