Class: CFA::Grub2::DeviceMap

Inherits:
BaseModel
  • Object
show all
Defined in:
lib/cfa/grub2/device_map.rb

Overview

Represents grub device map in /boot/grub2/device_map for details see www.gnu.org/software/grub/manual/html_node/Device-map.html Main features:

  • Do not overwrite files

  • When setting value first try to just change value if key already exists

  • When grub key is not there, then add to file

  • checks and raise exception if number of mappings exceed limit 8. Limitation is caused by BIOS Int 13 used by grub2 for selecting boot device.

Constant Summary collapse

PARSER = 
AugeasParser.new("device_map.lns")
PATH = 
"/boot/grub2/device.map".freeze

Instance Method Summary collapse

Constructor Details

#initialize(file_handler: nil) ⇒ DeviceMap

Returns a new instance of DeviceMap.



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# File 'lib/cfa/grub2/device_map.rb', line 22

def initialize(file_handler: nil)
  super(PARSER, PATH, file_handler: file_handler)
end

Instance Method Details

#add_mapping(grub_device, system_device) ⇒ Object

Note:

if mapping for given grub device is already defined, it will be overwritten

Appends to configuration mapping between grub_device and system_device



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# File 'lib/cfa/grub2/device_map.rb', line 48

def add_mapping(grub_device, system_device)
  generic_set(grub_device, system_device)
end

#grub_device_for(system_dev) ⇒ String

Returns grub device name for given system device.

Returns:

  • (String) —

    grub device name for given system device



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# File 'lib/cfa/grub2/device_map.rb', line 33

def grub_device_for(system_dev)
  matcher = Matcher.new(value_matcher: system_dev)
  entry = data.select(matcher)

  entry.empty? ? nil : entry.first[:key]
end

#grub_devices ⇒ Array<String>

Returns list of all grub devices which have mapping. If there is no mapping, then it return empty list.

Returns:

  • (Array<String>) —

    list of all grub devices which have mapping. If there is no mapping, then it return empty list.



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# File 'lib/cfa/grub2/device_map.rb', line 59

def grub_devices
  matcher = Matcher.new { |k, _v| k !~ /comment/ }
  entries = data.select(matcher)

  entries.map { |e| e[:key] }
end

#remove_mapping(grub_device) ⇒ Object

Removes mapping for given grub device



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# File 'lib/cfa/grub2/device_map.rb', line 53

def remove_mapping(grub_device)
  data.delete(grub_device)
end

#save(changes_only: false) ⇒ Object 



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# File 'lib/cfa/grub2/device_map.rb', line 26

def save(changes_only: false)
  raise "Too many grub devices. Limit is 8." if grub_devices.size > 8

  super
end

#system_device_for(grub_device) ⇒ String

Returns system device name for given grub device.

Returns:

  • (String) —

    system device name for given grub device



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# File 'lib/cfa/grub2/device_map.rb', line 41

def system_device_for(grub_device)
  data[grub_device]
end