runtime/objc-load.m

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25
  26 /*
  27  *      objc-load.m
  28  *      Copyright 1988-1996, NeXT Software, Inc.
  29  *      Author: s. naroff
  30  *
  31  */
  32
  33 #import "objc-private.h"
  34 #import <objc/objc-runtime.h>
  35 #import <objc/hashtable2.h>
  36 #import <objc/Object.h>
  37 #import <objc/Protocol.h>
  38
  39 //#import <streams/streams.h>
  40
  41 #include <mach-o/dyld.h>
  42
  43
  44
  45
  46 extern char *   getsectdatafromheader   (const headerType * mhp, const char * segname, const char * sectname,  int * size);
  47
  48 /* Private extern */
  49 OBJC_EXPORT void (*callbackFunction)( Class, const char * );
  50
  51
  52 /**********************************************************************************
  53 * objc_loadModule.
  54 *
  55 * NOTE: Loading isn't really thread safe.  If a load message recursively calls
  56 * objc_loadModules() both sets will be loaded correctly, but if the original
  57 * caller calls objc_unloadModules() it will probably unload the wrong modules.
  58 * If a load message calls objc_unloadModules(), then it will unload
  59 * the modules currently being loaded, which will probably cause a crash.
  60 *
  61 * Error handling is still somewhat crude.  If we encounter errors while
  62 * linking up classes or categories, we will not recover correctly.
  63 *
  64 * I removed attempts to lock the class hashtable, since this introduced
  65 * deadlock which was hard to remove.  The only way you can get into trouble
  66 * is if one thread loads a module while another thread tries to access the
  67 * loaded classes (using objc_lookUpClass) before the load is complete.
  68 **********************************************************************************/
  69 int objc_loadModule(const char *moduleName, void (*class_callback) (Class, const char *categoryName), int *errorCode)
  70 {
  71     int                                                         successFlag = 1;
  72     int                                                         locErrorCode;
  73     NSObjectFileImage                           objectFileImage;
  74     NSObjectFileImageReturnCode         code;
  75
  76     // So we don't have to check this everywhere
  77     if (errorCode == NULL)
  78         errorCode = &locErrorCode;
  79
  80     if (moduleName == NULL)
  81     {
  82         *errorCode = NSObjectFileImageInappropriateFile;
  83         return 0;
  84     }
  85
  86     if (_dyld_present () == 0)
  87     {
  88         *errorCode = NSObjectFileImageFailure;
  89         return 0;
  90     }
  91
  92     callbackFunction = class_callback;
  93     code = NSCreateObjectFileImageFromFile (moduleName, &objectFileImage);
  94     if (code != NSObjectFileImageSuccess)
  95     {
  96         *errorCode = code;
  97         return 0;
  98     }
  99
 100     if (NSLinkModule(objectFileImage, moduleName, NSLINKMODULE_OPTION_RETURN_ON_ERROR) == NULL) {
 101         NSLinkEditErrors error;
 102         int errorNum;
 103         char *fileName, *errorString;
 104         NSLinkEditError(&error, &errorNum, &fileName, &errorString);
 105         // These errors may overlap with other errors that objc_loadModule returns in other failure cases.
 106         *errorCode = error;
 107         return 0;
 108     }
 109     callbackFunction = NULL;
 110
 111
 112     return successFlag;
 113 }
 114
 115 /**********************************************************************************
 116 * objc_loadModules.
 117 **********************************************************************************/
 118 /* Lock for dynamic loading and unloading. */
 119 //      static OBJC_DECLARE_LOCK (loadLock);
 120
 121
 122 long    objc_loadModules   (char *                      modlist[],
 123                          void *                 errStream,
 124                          void                   (*class_callback) (Class, const char *),
 125                          headerType **  hdr_addr,
 126                          char *                 debug_file)
 127 {
 128     char **                             modules;
 129     int                                 code;
 130     int                                 itWorked;
 131
 132     if (modlist == 0)
 133         return 0;
 134
 135     for (modules = &modlist[0]; *modules != 0; modules++)
 136     {
 137         itWorked = objc_loadModule (*modules, class_callback, &code);
 138         if (itWorked == 0)
 139         {
 140             //if (errStream)
 141             //  NXPrintf ((NXStream *) errStream, "objc_loadModules(%s) code = %d\n", *modules, code);
 142             return 1;
 143         }
 144
 145         if (hdr_addr)
 146             *(hdr_addr++) = 0;
 147     }
 148
 149     return 0;
 150 }
 151
 152 /**********************************************************************************
 153 * objc_unloadModules.
 154 *
 155 * NOTE:  Unloading isn't really thread safe.  If an unload message calls
 156 * objc_loadModules() or objc_unloadModules(), then the current call
 157 * to objc_unloadModules() will probably unload the wrong stuff.
 158 **********************************************************************************/
 159
 160 long    objc_unloadModules (void *                      errStream,
 161                          void                   (*unload_callback) (Class, Category))
 162 {
 163     headerType *        header_addr = 0;
 164     int errflag = 0;
 165
 166     // TODO: to make unloading work, should get the current header
 167
 168     if (header_addr)
 169     {
 170         ; // TODO: unload the current header
 171     }
 172     else
 173     {
 174         errflag = 1;
 175     }
 176
 177     return errflag;
 178 }
 179