libsecurity_utilities/lib/macho++.h

   1 /*
   2  * Copyright (c) 2006 Apple Computer, 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 // macho++ - Mach-O object file helpers
  26 //
  27 #ifndef _H_MACHOPLUSPLUS
  28 #define _H_MACHOPLUSPLUS
  29
  30 #include <mach-o/loader.h>
  31 #include <mach-o/fat.h>
  32 #include <mach-o/arch.h>
  33 #include <security_utilities/globalizer.h>
  34 #include <security_utilities/endian.h>
  35 #include <security_utilities/unix++.h>
  36 #include <security_utilities/cfutilities.h>
  37
  38 namespace Security {
  39
  40
  41 //
  42 // An architecture specification.
  43 // Simply a pair or (cpu type, cpu subtype), really.
  44 //
  45 class Architecture : public std::pair<cpu_type_t, cpu_subtype_t> {
  46         typedef std::pair<cpu_type_t, cpu_subtype_t> _Pair;
  47 public:
  48         Architecture() { }
  49         explicit Architecture(cpu_type_t type, cpu_subtype_t sub = CPU_SUBTYPE_MULTIPLE)
  50                 : std::pair<cpu_type_t, cpu_subtype_t>(type, sub) { }
  51         Architecture(const fat_arch &archInFile);
  52         Architecture(const char *name);
  53
  54         cpu_type_t cpuType() const { return this->first; }
  55         cpu_subtype_t cpuSubtype() const { return this->second; }
  56         const char *name() const;                       // NULL if unknown
  57         std::string displayName() const;        // always display-able
  58
  59         static const cpu_type_t none = 0;
  60         operator bool () const { return cpuType() != none; }
  61         bool operator ! () const { return cpuType() == none; }
  62
  63 public:
  64         friend bool operator == (const Architecture &a1, const Architecture &a2)
  65         { return _Pair(a1) == _Pair(a2); }
  66
  67         friend bool operator < (const Architecture &a1, const Architecture &a2)
  68         { return _Pair(a1) < _Pair(a2); }
  69
  70         bool matches(const Architecture &templ) const;
  71
  72 public:
  73         static Architecture local();
  74 };
  75
  76
  77 //
  78 // Common features of Mach-O object images.
  79 // MachOBase does not define where we get this from.
  80 //
  81 class MachOBase {
  82 protected:
  83         virtual ~MachOBase();
  84
  85 public:
  86         template <class T>
  87         T flip(T value) const
  88         { return mFlip ? Security::flip(value) : value; }
  89
  90         bool isFlipped() const { return mFlip; }
  91         bool is64() const { return m64; }
  92
  93         const mach_header &header() const { return *mHeader; }
  94         Architecture architecture() const;
  95         uint32_t type() const;
  96         uint32_t flags() const;
  97
  98         const load_command *loadCommands() const { return mCommands; }
  99         const load_command *nextCommand(const load_command *command) const;
 100         size_t commandLength() const { return flip(mHeader->sizeofcmds); }
 101
 102         const load_command *findCommand(uint32_t cmd) const;
 103         const segment_command *findSegment(const char *segname) const;
 104         const section *findSection(const char *segname, const char *sectname) const;
 105
 106         const char *string(const load_command *cmd, const lc_str &str) const;
 107
 108         const linkedit_data_command *findCodeSignature() const;
 109         const linkedit_data_command *findLibraryDependencies() const;
 110
 111         size_t signingOffset() const;   // starting offset of CS section, or 0 if none
 112         size_t signingLength() const;   // length of CS section, or 0 if none
 113
 114 protected:
 115         void initHeader(const mach_header *address);
 116         void initCommands(const load_command *commands);
 117
 118         size_t headerSize() const;              // size of header
 119         size_t commandSize() const;             // size of commands area
 120
 121 private:
 122         const mach_header *mHeader;     // Mach-O header
 123         const load_command *mCommands; // load commands
 124         const load_command *mEndCommands; // end of load commands
 125
 126         bool m64;                                       // is 64-bit
 127         bool mFlip;                                     // wrong byte order (flip all integers)
 128 };
 129
 130
 131 //
 132 // A Mach-O object image that resides on disk.
 133 // We only read small parts of the contents into (discontinuous) memory.
 134 //
 135 class MachO : public MachOBase, public UnixPlusPlus::FileDesc {
 136 public:
 137         MachO(FileDesc fd, size_t offset = 0, size_t length = 0);
 138         ~MachO();
 139
 140         size_t offset() const { return mOffset; }
 141         size_t length() const { return mLength; }
 142         size_t signingExtent() const;   // signingOffset, or file length if none
 143
 144         void seek(size_t offset);       // relative to start of image
 145         CFDataRef dataAt(size_t offset, size_t size);
 146
 147 private:
 148         size_t mOffset;                 // starting file offset
 149         size_t mLength;                 // Mach-O file length
 150
 151         mach_header mHeaderBuffer; // read-in Mach-O header
 152         load_command *mCommandBuffer; // read-in (malloc'ed) Mach-O load commands
 153 };
 154
 155
 156 //
 157 // A Mach-O object image that was mapped into memory.
 158 // We expect the entire image to be contiguously mapped starting at the
 159 // address given. No particular alignment is required (beyond native
 160 // alignment constraints on member variables).
 161 //
 162 class MachOImage : public MachOBase {
 163 public:
 164         MachOImage(const void *address);
 165
 166         const void *address() { return &this->header(); }
 167 };
 168
 169 class MainMachOImage : public MachOImage {
 170 public:
 171         MainMachOImage();
 172
 173         static const void *mainImageAddress();
 174 };
 175
 176
 177 //
 178 // A Universal object represents a Mach-O binary image (whole) file.
 179 // It can represent a true Universal (aka "Fat") file with multiple
 180 // architectures; but it will also represent a single Mach-O ("thin")
 181 // binary and make you believe it's a Universal with just one architecture.
 182 //
 183 class Universal : public UnixPlusPlus::FileDesc {
 184 public:
 185         Universal(FileDesc fd, off_t offset = 0);
 186         ~Universal();
 187
 188         // return a genuine MachO object for the given architecture
 189         MachO *architecture() const;            // native
 190         MachO *architecture(const Architecture &arch) const; // given
 191         MachO *architecture(off_t offset) const; // given by file offset
 192
 193         // return (just) the starting offset of an architecture
 194         size_t archOffset() const;                      // native
 195         size_t archOffset(const Architecture &arch) const; // given
 196
 197         // return a set of architectures contained
 198         typedef std::set<Architecture> Architectures;
 199         void architectures(Architectures &archs);
 200
 201         bool isUniversal() const { return mArchList != NULL; }
 202         Architecture bestNativeArch() const;
 203
 204 public:
 205         static uint32_t typeOf(FileDesc fd);
 206
 207 private:
 208         const fat_arch *findArch(const Architecture &arch) const;
 209         MachO *findImage(const Architecture &arch) const;
 210
 211 private:
 212         fat_arch *mArchList;            // architectures (NULL if thin file)
 213         unsigned mArchCount;            // number of architectures (if fat)
 214         Architecture mThinArch;         // single architecture (if thin)
 215         off_t mBase;                            // overriding offset in file (all types)
 216 };
 217
 218
 219 } // end namespace Security
 220
 221 #endif // !_H_MACHOPLUSPLUS