runtime/objc-file.mm

   1 /*
   2  * Copyright (c) 1999-2007 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 #if __OBJC2__
  25
  26 #include "objc-private.h"
  27 #include "objc-file.h"
  28
  29 // Segment and section names are 16 bytes and may be un-terminated.
  30 bool segnameEquals(const char *lhs, const char *rhs) {
  31     return 0 == strncmp(lhs, rhs, 16);
  32 }
  33
  34 bool segnameStartsWith(const char *segname, const char *prefix) {
  35     return 0 == strncmp(segname, prefix, strlen(prefix));
  36 }
  37
  38 bool sectnameEquals(const char *lhs, const char *rhs) {
  39     return segnameEquals(lhs, rhs);
  40 }
  41
  42 bool sectnameStartsWith(const char *sectname, const char *prefix) {
  43     return segnameStartsWith(sectname, prefix);
  44 }
  45
  46
  47 // Look for a __DATA or __DATA_CONST or __DATA_DIRTY section
  48 // with the given name that stores an array of T.
  49 template <typename T>
  50 T* getDataSection(const headerType *mhdr, const char *sectname,
  51                   size_t *outBytes, size_t *outCount)
  52 {
  53     unsigned long byteCount = 0;
  54     T* data = (T*)getsectiondata(mhdr, "__DATA", sectname, &byteCount);
  55     if (!data) {
  56         data = (T*)getsectiondata(mhdr, "__DATA_CONST", sectname, &byteCount);
  57     }
  58     if (!data) {
  59         data = (T*)getsectiondata(mhdr, "__DATA_DIRTY", sectname, &byteCount);
  60     }
  61     if (outBytes) *outBytes = byteCount;
  62     if (outCount) *outCount = byteCount / sizeof(T);
  63     return data;
  64 }
  65
  66 #define GETSECT(name, type, sectname)                                   \
  67     type *name(const headerType *mhdr, size_t *outCount) {              \
  68         return getDataSection<type>(mhdr, sectname, nil, outCount);     \
  69     }                                                                   \
  70     type *name(const header_info *hi, size_t *outCount) {               \
  71         return getDataSection<type>(hi->mhdr, sectname, nil, outCount); \
  72     }
  73
  74 //      function name                 content type     section name
  75 GETSECT(_getObjc2SelectorRefs,        SEL,             "__objc_selrefs");
  76 GETSECT(_getObjc2MessageRefs,         message_ref_t,   "__objc_msgrefs");
  77 GETSECT(_getObjc2ClassRefs,           Class,           "__objc_classrefs");
  78 GETSECT(_getObjc2SuperRefs,           Class,           "__objc_superrefs");
  79 GETSECT(_getObjc2ClassList,           classref_t,      "__objc_classlist");
  80 GETSECT(_getObjc2NonlazyClassList,    classref_t,      "__objc_nlclslist");
  81 GETSECT(_getObjc2CategoryList,        category_t *,    "__objc_catlist");
  82 GETSECT(_getObjc2NonlazyCategoryList, category_t *,    "__objc_nlcatlist");
  83 GETSECT(_getObjc2ProtocolList,        protocol_t *,    "__objc_protolist");
  84 GETSECT(_getObjc2ProtocolRefs,        protocol_t *,    "__objc_protorefs");
  85 GETSECT(getLibobjcInitializers,       Initializer,   "__objc_init_func");
  86
  87
  88 objc_image_info *
  89 _getObjcImageInfo(const headerType *mhdr, size_t *outBytes)
  90 {
  91     return getDataSection<objc_image_info>(mhdr, "__objc_imageinfo",
  92                                            outBytes, nil);
  93 }
  94
  95
  96 static const segmentType *
  97 getsegbynamefromheader(const headerType *mhdr, const char *segname)
  98 {
  99     const segmentType *seg = (const segmentType *) (mhdr + 1);
 100     for (unsigned long i = 0; i < mhdr->ncmds; i++){
 101         if (seg->cmd == SEGMENT_CMD  &&  segnameEquals(seg->segname, segname)) {
 102             return seg;
 103         }
 104         seg = (const segmentType *)((char *)seg + seg->cmdsize);
 105     }
 106     return nil;
 107 }
 108
 109 // Look for an __objc* section other than __objc_imageinfo
 110 static bool segmentHasObjcContents(const segmentType *seg)
 111 {
 112     if (seg) {
 113         for (uint32_t i = 0; i < seg->nsects; i++) {
 114             const sectionType *sect = ((const sectionType *)(seg+1))+i;
 115             if (sectnameStartsWith(sect->sectname, "__objc_")  &&
 116                 !sectnameEquals(sect->sectname, "__objc_imageinfo"))
 117             {
 118                 return true;
 119             }
 120         }
 121     }
 122
 123     return false;
 124 }
 125
 126 // Look for an __objc* section other than __objc_imageinfo
 127 bool
 128 _hasObjcContents(const header_info *hi)
 129 {
 130     const segmentType *data =
 131         getsegbynamefromheader(hi->mhdr, "__DATA");
 132     const segmentType *data_const =
 133         getsegbynamefromheader(hi->mhdr, "__DATA_CONST");
 134     const segmentType *data_dirty =
 135         getsegbynamefromheader(hi->mhdr, "__DATA_CONST");
 136
 137     return segmentHasObjcContents(data)
 138         || segmentHasObjcContents(data_const)
 139         || segmentHasObjcContents(data_dirty);
 140 }
 141
 142 #endif