Class: MachO::MachHeader

Inherits:
MachOStructure show all
Defined in:
lib/macho/headers.rb

Overview

32-bit Mach-O file header structure

Direct Known Subclasses

MachHeader64

Constant Summary collapse

FORMAT =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

See Also:

"L=7".freeze
SIZEOF =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

See Also:

28

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from MachOStructure

bytesize, new_from_bin

Constructor Details

#initialize(magic, cputype, cpusubtype, filetype, ncmds, sizeofcmds, flags) ⇒ MachHeader

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of MachHeader.



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# File 'lib/macho/headers.rb', line 543

def initialize(magic, cputype, cpusubtype, filetype, ncmds, sizeofcmds,
               flags)
  @magic = magic
  @cputype = cputype
  # For now we're not interested in additional capability bits also to be
  # found in the `cpusubtype` field. We only care about the CPU sub-type.
  @cpusubtype = cpusubtype & ~CPU_SUBTYPE_MASK
  @filetype = filetype
  @ncmds = ncmds
  @sizeofcmds = sizeofcmds
  @flags = flags
end

Instance Attribute Details

#cpusubtype ⇒ Fixnum (readonly)

Returns the CPU subtype of the Mach-O.

Returns:

  • (Fixnum) —

    the CPU subtype of the Mach-O



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# File 'lib/macho/headers.rb', line 520

def cpusubtype
  @cpusubtype
end

#cputype ⇒ Fixnum (readonly)

Returns the CPU type of the Mach-O.

Returns:

  • (Fixnum) —

    the CPU type of the Mach-O



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# File 'lib/macho/headers.rb', line 517

def cputype
  @cputype
end

#filetype ⇒ Fixnum (readonly)

Returns the file type of the Mach-O.

Returns:

  • (Fixnum) —

    the file type of the Mach-O



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# File 'lib/macho/headers.rb', line 523

def filetype
  @filetype
end

#flags ⇒ Fixnum (readonly)

Returns the header flags associated with the Mach-O.

Returns:

  • (Fixnum) —

    the header flags associated with the Mach-O



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# File 'lib/macho/headers.rb', line 532

def flags
  @flags
end

#magic ⇒ Fixnum (readonly)

Returns the magic number.

Returns:

  • (Fixnum) —

    the magic number



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# File 'lib/macho/headers.rb', line 514

def magic
  @magic
end

#ncmds ⇒ Fixnum (readonly)

Returns the number of load commands in the Mach-O.

Returns:

  • (Fixnum) —

    the number of load commands in the Mach-O



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# File 'lib/macho/headers.rb', line 526

def ncmds
  @ncmds
end

#sizeofcmds ⇒ Fixnum (readonly)

Returns the size of all load commands, in bytes, in the Mach-O.

Returns:

  • (Fixnum) —

    the size of all load commands, in bytes, in the Mach-O



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# File 'lib/macho/headers.rb', line 529

def sizeofcmds
  @sizeofcmds
end

Instance Method Details

#flag?(flag) ⇒ Boolean

Returns true if flag is present in the header's flag section.

Examples:

puts "this mach-o has position-independent execution" if header.flag?(:MH_PIE)

Parameters:

  • flag (Symbol) —

    a mach header flag symbol

Returns:

  • (Boolean) —

    true if flag is present in the header's flag section



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# File 'lib/macho/headers.rb', line 560

def flag?(flag)
  flag = MH_FLAGS[flag]
  return false if flag.nil?
  flags & flag == flag
end