dyld3/MachOLoaded.h

   1 /*
   2  * Copyright (c) 2017 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 #ifndef MachOLoaded_h
  25 #define MachOLoaded_h
  26
  27 #include <stdint.h>
  28
  29 #include "MachOFile.h"
  30
  31
  32 class CacheBuilder;
  33
  34 namespace dyld3 {
  35
  36
  37 // A mach-o mapped into memory with zero-fill expansion
  38 // Can be used in dyld at runtime or during closure building
  39 struct VIS_HIDDEN MachOLoaded : public MachOFile
  40 {
  41         typedef const MachOLoaded* (^DependentToMachOLoaded)(const MachOLoaded* image, uint32_t depIndex);
  42
  43     // for dlsym()
  44         bool                hasExportedSymbol(const char* symbolName, DependentToMachOLoaded finder, void** result,
  45                                           bool* resultPointsToInstructions) const;
  46
  47     // for DYLD_PRINT_SEGMENTS
  48     const char*         segmentName(uint32_t segIndex) const;
  49
  50     // used to see if main executable overlaps shared region
  51     bool                intersectsRange(uintptr_t start, uintptr_t length) const;
  52
  53     // for _dyld_get_image_slide()
  54     intptr_t            getSlide() const;
  55
  56     // quick check if image has been incorporated into the dyld cache
  57     bool                   inDyldCache() const { return (this->flags & 0x80000000); }
  58
  59     // for dladdr()
  60     bool                findClosestSymbol(uint64_t unSlidAddr, const char** symbolName, uint64_t* symbolUnslidAddr) const;
  61
  62     // for _dyld_find_unwind_sections()
  63     const void*         findSectionContent(const char* segName, const char* sectName, uint64_t& size) const;
  64
  65     // used at runtime to validate loaded image matches closure
  66     bool                cdHashOfCodeSignature(const void* codeSigStart, size_t codeSignLen, uint8_t cdHash[20]) const;
  67
  68     // used by DyldSharedCache to find closure
  69     static const uint8_t*   trieWalk(Diagnostics& diag, const uint8_t* start, const uint8_t* end, const char* symbol);
  70
  71     // used by cache builder during error handling in chain bind processing
  72     const char*             dependentDylibLoadPath(uint32_t depIndex) const;
  73
  74     // used by closure builder to find the offset and size of the trie.
  75     bool                    hasExportTrie(uint32_t& runtimeOffset, uint32_t& size) const;
  76
  77
  78     // For use with new rebase/bind scheme were each fixup location on disk contains info on what
  79     // fix up it needs plus the offset to the next fixup.
  80     union ChainedFixupPointerOnDisk
  81     {
  82         struct PlainRebase
  83         {
  84             uint64_t    target   : 51,
  85                         next     : 11,
  86                         bind     :  1,    // 0
  87                         auth     :  1;    // 0
  88             uint64_t    signExtendedTarget() const;
  89         };
  90         struct PlainBind
  91         {
  92             uint64_t    ordinal   : 16,
  93                         zero      : 16,
  94                         addend    : 19,
  95                         next      : 11,
  96                         bind      :  1,    // 1
  97                         auth      :  1;    // 0
  98             uint64_t    signExtendedAddend() const;
  99         };
 100         struct AuthRebase
 101         {
 102             uint64_t    target    : 32,
 103                         diversity : 16,
 104                         addrDiv   :  1,
 105                         key       :  2,
 106                         next      : 11,
 107                         bind      :  1,    // 0
 108                         auth      :  1;    // 1
 109             const char* keyName() const;
 110         };
 111         struct AuthBind
 112         {
 113             uint64_t    ordinal   : 16,
 114                         zero      : 16,
 115                         diversity : 16,
 116                         addrDiv   :  1,
 117                         key       :  2,
 118                         next      : 11,
 119                         bind      :  1,    // 1
 120                         auth      :  1;    // 1
 121             const char* keyName() const;
 122         };
 123
 124         uint64_t        raw;
 125         AuthRebase      authRebase;
 126         AuthBind        authBind;
 127         PlainRebase     plainRebase;
 128         PlainBind       plainBind;
 129
 130         static const char*  keyName(uint8_t keyBits);
 131         static uint64_t     signExtend51(uint64_t);
 132         uint64_t            signPointer(void* loc, uint64_t target) const;
 133      };
 134
 135 protected:
 136     friend CacheBuilder;
 137
 138     struct FoundSymbol {
 139         enum class Kind { headerOffset, absolute, resolverOffset };
 140         Kind                kind;
 141         bool                isThreadLocal;
 142         bool                isWeakDef;
 143         const MachOLoaded*  foundInDylib;
 144         uint64_t            value;
 145         uint32_t            resolverFuncOffset;
 146         const char*         foundSymbolName;
 147     };
 148
 149      struct LayoutInfo {
 150         uintptr_t    slide;
 151         uintptr_t    textUnslidVMAddr;
 152         uintptr_t    linkeditUnslidVMAddr;
 153         uint32_t     linkeditFileOffset;
 154         uint32_t     linkeditFileSize;
 155         uint32_t     linkeditSegIndex;
 156     };
 157
 158     struct LinkEditInfo
 159     {
 160         const dyld_info_command*     dyldInfo;
 161         const symtab_command*        symTab;
 162         const dysymtab_command*      dynSymTab;
 163         const linkedit_data_command* splitSegInfo;
 164         const linkedit_data_command* functionStarts;
 165         const linkedit_data_command* dataInCode;
 166         const linkedit_data_command* codeSig;
 167         LayoutInfo                   layout;
 168     };
 169
 170     bool                    findExportedSymbol(Diagnostics& diag, const char* symbolName, FoundSymbol& foundInfo, DependentToMachOLoaded finder) const;
 171     void                    getLinkEditPointers(Diagnostics& diag, LinkEditInfo&) const;
 172     void                    getLinkEditLoadCommands(Diagnostics& diag, LinkEditInfo& result) const;
 173     void                    getLayoutInfo(LayoutInfo&) const;
 174     const uint8_t*          getLinkEditContent(const LayoutInfo& info, uint32_t fileOffset) const;
 175     void                    forEachGlobalSymbol(Diagnostics& diag, void (^callback)(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, bool& stop)) const;
 176     void                    forEachLocalSymbol(Diagnostics& diag, void (^callback)(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, bool& stop)) const;
 177     uint32_t                dependentDylibCount() const;
 178     bool                    findClosestFunctionStart(uint64_t address, uint64_t* functionStartAddress) const;
 179
 180     const void*             findCodeDirectoryBlob(const void* codeSigStart, size_t codeSignLen) const;
 181
 182 };
 183
 184 } // namespace dyld3
 185
 186 #endif /* MachOLoaded_h */