Home | History | Annotate | Download | only in mac 
      1 // Copyright (c) 2006, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 // macho_walker.h: Iterate over the load commands in a mach-o file
     31 //
     32 // Author: Dan Waylonis
     33 
     34 #ifndef COMMON_MAC_MACHO_WALKER_H__
     35 #define COMMON_MAC_MACHO_WALKER_H__
     36 
     37 #include <mach/machine.h>
     38 #include <mach-o/loader.h>
     39 #include <sys/types.h>
     40 
     41 namespace MacFileUtilities {
     42 
     43 class MachoWalker {
     44  public:
     45   // A callback function executed when a new load command is read.  If no
     46   // further processing of load commands is desired, return false.  Otherwise,
     47   // return true.
     48   // |cmd| is the current command, and |offset| is the location relative to the
     49   // beginning of the file (not header) where the command was read.  If |swap|
     50   // is set, then any command data (other than the returned load_command) should
     51   // be swapped when read
     52   typedef bool (*LoadCommandCallback)(MachoWalker *walker, load_command *cmd,
     53                                       off_t offset, bool swap, void *context);
     54 
     55   MachoWalker(const char *path, LoadCommandCallback callback, void *context);
     56   MachoWalker(void *memory, size_t size, LoadCommandCallback callback,
     57               void *context);
     58   ~MachoWalker();
     59 
     60   // Begin walking the header for |cpu_type| and |cpu_subtype|.  If |cpu_type|
     61   // is 0, then the native cpu type is used. Otherwise, accepted values are
     62   // listed in /usr/include/mach/machine.h (e.g., CPU_TYPE_X86 or
     63   // CPU_TYPE_POWERPC). If |cpu_subtype| is CPU_SUBTYPE_MULTIPLE, the match is
     64   // only done on |cpu_type|.
     65   // Returns false if opening the file failed or if the |cpu_type|/|cpu_subtype|
     66   // is not present in the file.
     67   bool WalkHeader(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype);
     68 
     69   // Read |size| bytes from the opened file at |offset| into |buffer|
     70   bool ReadBytes(void *buffer, size_t size, off_t offset);
     71 
     72   // Return the current header and header offset
     73   bool CurrentHeader(struct mach_header_64 *header, off_t *offset);
     74 
     75  private:
     76   // Locate (if any) the header offset for |cpu_type| and return in |offset|.
     77   // Return true if found, false otherwise.
     78   bool FindHeader(cpu_type_t cpu_type,
     79                   cpu_subtype_t cpu_subtype,
     80                   off_t &offset);
     81 
     82   // Process an individual header starting at |offset| from the start of the
     83   // file.  Return true if successful, false otherwise.
     84   bool WalkHeaderAtOffset(off_t offset);
     85   bool WalkHeader64AtOffset(off_t offset);
     86 
     87   // Bottleneck for walking the load commands
     88   bool WalkHeaderCore(off_t offset, uint32_t number_of_commands, bool swap);
     89 
     90   // File descriptor to the opened file
     91   int file_;
     92 
     93   // Memory location to read from.
     94   void *memory_;
     95 
     96   // Size of the memory segment we can read from.
     97   size_t memory_size_;
     98 
     99   // User specified callback & context
    100   LoadCommandCallback callback_;
    101   void *callback_context_;
    102 
    103   // Current header, size, and offset.  The mach_header_64 is used for both
    104   // 32-bit and 64-bit headers because they only differ in their last field
    105   // (reserved).  By adding the |current_header_size_| and the
    106   // |current_header_offset_|, you can determine the offset in the file just
    107   // after the header.
    108   struct mach_header_64 *current_header_;
    109   unsigned long current_header_size_;
    110   off_t current_header_offset_;
    111 
    112  private:
    113   MachoWalker(const MachoWalker &);
    114   MachoWalker &operator=(const MachoWalker &);
    115 };
    116 
    117 }  // namespace MacFileUtilities
    118 
    119 #endif  // COMMON_MAC_MACHO_WALKER_H__
    120