class Facter::Util::Windows::FFI

Constants

ERROR_SUCCESS
NULL_HANDLE
WIN32_FALSE

standard Win32 error codes

Public Class Methods

read_arbitrary_wide_string_up_to(ffi_pointer, max_char_length = 512, null_terminator = :single_null) click to toggle source

@param max_char_length [Integer] Maximum number of wide chars to return (typically excluding NULLs), not bytes @param null_terminator [Symbol] Number of number of null wchar characters, not bytes, that determine the end of the string

null_terminator = :single_null, then the terminating sequence is two bytes of zero.   This is UNIT16 = 0
null_terminator = :double_null, then the terminating sequence is four bytes of zero.  This is UNIT32 = 0
# File lib/facter/util/windows/api_types.rb, line 35
def self.read_arbitrary_wide_string_up_to(ffi_pointer, max_char_length = 512, null_terminator = :single_null)
  if null_terminator != :single_null && null_terminator != :double_null
    raise _("Unable to read wide strings with %{null_terminator} terminal nulls") % { null_terminator: null_terminator }
  end

  terminator_width = null_terminator == :single_null ? 1 : 2
  reader_method = null_terminator == :single_null ? :get_uint16 : :get_uint32

  # Look for a null terminating characters; if found, read up to that null (exclusive)

  (0...max_char_length - terminator_width).each do |i|
    return read_wide_string(ffi_pointer, i) if ffi_pointer.send(reader_method, (i * 2)) == 0
  end

  # String is longer than the max; read just to the max

  read_wide_string(ffi_pointer, max_char_length)
end
read_dword(ffi_pointer) click to toggle source
# File lib/facter/util/windows/api_types.rb, line 17
def self.read_dword(ffi_pointer)
  ffi_pointer.read_uint32
end
read_handle(ffi_pointer) click to toggle source
# File lib/facter/util/windows/api_types.rb, line 21
def self.read_handle(ffi_pointer)
  ffi_pointer.type_size == 4 ? ffi_pointer.read_uint32 : ffi_pointer.read_uint64
end
read_wide_string(ffi_pointer, char_length, dst_encoding = Encoding::UTF_8) click to toggle source
# File lib/facter/util/windows/api_types.rb, line 25
def self.read_wide_string(ffi_pointer, char_length, dst_encoding = Encoding::UTF_8)
  # char_length is number of wide chars (typically excluding NULLs), *not* bytes

  str = ffi_pointer.get_bytes(0, char_length * 2).force_encoding('UTF-16LE')
  str.encode(dst_encoding)
end
read_win32_bool(ffi_pointer) click to toggle source
# File lib/facter/util/windows/api_types.rb, line 11
def self.read_win32_bool(ffi_pointer)
  # BOOL is always a 32-bit integer in Win32

  # some Win32 APIs return 1 for true, while others are non-0

  ffi_pointer.read_int32 != WIN32_FALSE
end
read_win32_local_pointer(ffi_pointer) { |ptr| ... } click to toggle source
# File lib/facter/util/windows/api_types.rb, line 52
def self.read_win32_local_pointer(ffi_pointer, &block)
  ptr = nil
  begin
    ptr = ffi_pointer.read_pointer
    yield ptr
  ensure
    if ptr && ! ptr.null?
      if WIN32.LocalFree(ptr.address) != NULL_HANDLE
        Puppet.debug "LocalFree memory leak"
      end
    end
  end

  # ptr has already had LocalFree called, so nothing to return

  nil
end