The Tor Browser / file revision

 // Copyright (c) 2006, Google Inc.

 // All rights reserved.

 //

 // Redistribution and use in source and binary forms, with or without

 // modification, are permitted provided that the following conditions are

 // met:

 //

 //     * Redistributions of source code must retain the above copyright

 // notice, this list of conditions and the following disclaimer.

 //     * Redistributions in binary form must reproduce the above

 // copyright notice, this list of conditions and the following disclaimer

 // in the documentation and/or other materials provided with the

 // distribution.

 //     * Neither the name of Google Inc. nor the names of its

 // contributors may be used to endorse or promote products derived from

 // this software without specific prior written permission.

 //

 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 // macho_walker.h: Iterate over the load commands in a mach-o file

 //

 // Author: Dan Waylonis

 #ifndef COMMON_MAC_MACHO_WALKER_H__

 #define COMMON_MAC_MACHO_WALKER_H__

 #include <mach/machine.h>

 #include <mach-o/loader.h>

 #include <sys/types.h>

 namespace MacFileUtilities {

 class MachoWalker {

  public:

   // A callback function executed when a new load command is read.  If no

   // further processing of load commands is desired, return false.  Otherwise,

   // return true.

   // |cmd| is the current command, and |offset| is the location relative to the

   // beginning of the file (not header) where the command was read.  If |swap|

   // is set, then any command data (other than the returned load_command) should

   // be swapped when read

   typedef bool (*LoadCommandCallback)(MachoWalker *walker, load_command *cmd,

                                       off_t offset, bool swap, void *context);

   MachoWalker(const char *path, LoadCommandCallback callback, void *context);

   MachoWalker(void *memory, size_t size, LoadCommandCallback callback,

               void *context);

   ~MachoWalker();

   // Begin walking the header for |cpu_type| and |cpu_subtype|.  If |cpu_type|

   // is 0, then the native cpu type is used. Otherwise, accepted values are

   // listed in /usr/include/mach/machine.h (e.g., CPU_TYPE_X86 or

   // CPU_TYPE_POWERPC). If |cpu_subtype| is CPU_SUBTYPE_MULTIPLE, the match is

   // only done on |cpu_type|.

   // Returns false if opening the file failed or if the |cpu_type|/|cpu_subtype|

   // is not present in the file.

   bool WalkHeader(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype);

   // Read |size| bytes from the opened file at |offset| into |buffer|

   bool ReadBytes(void *buffer, size_t size, off_t offset);

   // Return the current header and header offset

   bool CurrentHeader(struct mach_header_64 *header, off_t *offset);

  private:

   // Locate (if any) the header offset for |cpu_type| and return in |offset|.

   // Return true if found, false otherwise.

   bool FindHeader(cpu_type_t cpu_type,

                   cpu_subtype_t cpu_subtype,

                   off_t &offset);

   // Process an individual header starting at |offset| from the start of the

   // file.  Return true if successful, false otherwise.

   bool WalkHeaderAtOffset(off_t offset);

   bool WalkHeader64AtOffset(off_t offset);

   // Bottleneck for walking the load commands

   bool WalkHeaderCore(off_t offset, uint32_t number_of_commands, bool swap);

   // File descriptor to the opened file

   int file_;

   // Memory location to read from.

   void *memory_;

   // Size of the memory segment we can read from.

   size_t memory_size_;

   // User specified callback & context

   LoadCommandCallback callback_;

   void *callback_context_;

   // Current header, size, and offset.  The mach_header_64 is used for both

   // 32-bit and 64-bit headers because they only differ in their last field

   // (reserved).  By adding the |current_header_size_| and the

   // |current_header_offset_|, you can determine the offset in the file just

   // after the header.

   struct mach_header_64 *current_header_;

   unsigned long current_header_size_;

   off_t current_header_offset_;

  private:

   MachoWalker(const MachoWalker &);

   MachoWalker &operator=(const MachoWalker &);

 };

 }  // namespace MacFileUtilities

 #endif  // COMMON_MAC_MACHO_WALKER_H__