Using FFI to read from fibre channel HBA dll on a Windows box

ffi_hba_dll.rb

require 'ffi'

class Fixnum
  def hex(numchars=16)
    self.to_s(numchars).upcase
  end
end

module FFI
class Struct
  class InlineArray
    def to_wwn
      wwnstruct = HBA::HBA_Wwn.new self.to_ptr
      wwn = wwnstruct[:wwn][0].hex
      1.upto(7) do |i|
        hex = wwnstruct[:wwn][i].hex
        if wwnstruct[:wwn][i] < 16
          hex = "0#{hex}"
        end
        wwn = "#{wwn}:#{hex}"
      end
      wwn
    end
  end
end
end

module HBA
  extend FFI::Library
  
  typedef :uint32, :handle
  
  class HBA_AdapterAttributes < FFI::Struct 
    layout :Manufacturer, [:char, 64], 
      :SerialNumber, [:char, 64], 
      :Model, [:char, 256], 
      :ModelDescription, [:char, 256], 
      :NodeWWN, [:uint8, 8], # this probably needs to be another struct 
      :NodeSymbolicName, [:char, 256], 
      :HardwareVersion, [:char, 256], 
      :DriverVersion, [:char, 256], 
      :OptionROMVersion, [:char, 256], 
      :FirmwareVersion, [:char, 256], 
      :VendorSpecificID, :uint32, 
      :NumberOfPorts, :int, 
      :DriverName, [:char, 256]
  end

  class HBA_Wwn < FFI::Struct
    layout :wwn, [:uint8, 8]
  end

  pwdir = Dir.getwd.gsub('/', '\\')
  ffi_lib 'C:\Program Files\QLogic Corporation\SANsurfer\ql2xhai2.dll'
  
  ffi_convention :stdcall

  # if we get a segmentation fault, the wrong data type was probably used
  attach_function :HBA_GetVersion, [], :uint32
  attach_function :HBA_GetNumberOfAdapters, [], :uint32
  attach_function :HBA_LoadLibrary, [], :uint32
  attach_function :HBA_GetAdapterName, [:uint32, :pointer], :uint32
  attach_function :HBA_OpenAdapter, [:pointer], :handle
  attach_function :HBA_CloseAdapter, [:uint32], :void
  attach_function :HBA_GetAdapterAttributes, [:handle, :pointer], :uint32
end

HBA.HBA_LoadLibrary
adapter_count = HBA.HBA_GetNumberOfAdapters
hba_version = HBA.HBA_GetVersion

puts "Version: #{hba_version}"
puts "Count: #{adapter_count}"
puts "-----------"

x = adapter_count - 1

(0..x).each do |i|
  adapter = FFI::MemoryPointer.new :char, 256
  HBA.HBA_GetAdapterName(i, adapter)
  handle = HBA.HBA_OpenAdapter(adapter.get_string(0))

  puts "Handle opened: #{handle}"
  puts "Adapter name: #{adapter.get_string(0)}"

  attribs = HBA::HBA_AdapterAttributes.new
  HBA::HBA_GetAdapterAttributes(i, attribs)

  puts "Manufacturer: #{attribs[:Manufacturer]}"
  puts "Serial: #{attribs[:SerialNumber]}"
  puts "Model: #{attribs[:Model]}"
  puts "Description: #{attribs[:ModelDescription]}"
  puts "NodeWWN: #{attribs[:NodeWWN].to_wwn}"
  puts "SymbolicName: #{attribs[:NodeSymbolicName]}"
  puts "HardwareVersion: #{attribs[:HardwareVersion]}"
  puts "DriverVersion: #{attribs[:DriverVersion]}"
  puts "OptionROMVersion: #{attribs[:OptionROMVersion]}"
  puts "FirmwareVersion: #{attribs[:FirmwareVersion]}"
  puts "VendorSpecificID: #{attribs[:VendorSpecificID]}"
  puts "NumberOfPorts: #{attribs[:NumberOfPorts]}"
  puts "DriverName: #{attribs[:DriverName]}"


  HBA.HBA_CloseAdapter(handle)
  puts "Handle closed"
  puts "-----------"
end