Class: Fstab

Inherits:
Object
  • Object
show all
Defined in:
lib/fstab.rb

Constant Summary collapse

VERSION = 
"0.1"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file = '/etc/fstab', opts = {}) ⇒ Fstab

if safe_mode true, non existing devices won’t be added to fstab. Adding a non existing device to fstab will raise an exception. Trying to add a device without a filesystem will also rise an exception



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# File 'lib/fstab.rb', line 9

def initialize(file = '/etc/fstab', opts = {})
  @file = file
  @contents = File.read file
  @backup = opts[:backup].nil? ? true : opts[:backup]
  @safe_mode = opts[:safe_mode].nil? ? true : opts[:safe_mode]
  @backup_dir = opts[:backup_dir] || '/etc/'
end

Class Method Details

.get_blkdev_fs_attrs(dev) ⇒ Object

returns 

:uuid   => UUID,
:label  => LABEL,
:fstype => FSTYPE,
:dev    => DEVICE

All the attributes except dev may be nil at any given time since device may not have a valid filesystem or label.

Raises:

  • (ArgumentError) 


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# File 'lib/fstab.rb', line 224

def self.get_blkdev_fs_attrs(dev)
  raise ArgumentError.new("Invalid device path") unless File.blockdev?(dev)
  blkid = `/sbin/blkid #{dev}`
  attrs = {}
  attrs[:uuid] = blkid.match(/UUID="(.*?)"/)[1] rescue nil
  attrs[:label] = blkid.match(/LABEL="(.*?)"/)[1] rescue nil
  attrs[:fstype] = blkid.match(/TYPE="(.*?)"/)[1] rescue nil
  attrs[:dev] = blkid.match(/\/dev\/(.*):/)[1] rescue nil
  attrs
end

.get_blockdev(id) ⇒ Object

Get block device from UUID/Label



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# File 'lib/fstab.rb', line 237

def self.get_blockdev(id)
  if File.blockdev?(id) and !File.symlink?(id)
    return id
  end
  path = nil
  # Try to get blockdev from UUID first, then label
  begin
    path = File.readlink("/dev/disk/by-uuid/#{id}")
  rescue
    path = File.readlink("/dev/disk/by-label/#{id}") 
  end
  "/dev/#{path.split('/').last}"
end

.get_label(dev) ⇒ Object 



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# File 'lib/fstab.rb', line 260

def self.get_label(dev)
  Fstab.get_blkdev_fs_attrs(dev)[:label]
end

.get_uuid(dev) ⇒ Object 



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# File 'lib/fstab.rb', line 251

def self.get_uuid(dev)
  #`/sbin/blkid #{dev}`.match(/UUID="(.*?)"/)[1] rescue nil
  Fstab.get_blkdev_fs_attrs(dev)[:uuid]
end

.get_uuid_from_label(label) ⇒ Object 



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# File 'lib/fstab.rb', line 256

def self.get_uuid_from_label(label)
  Fstab.get_blkdev_fs_attrs("/dev/disk/by-label/#{label}")[:uuid]
end

Instance Method Details

#add_entry(opts = {}) ⇒ Object

:label => label or :uuid => uuid or :dev => dev_path :mount_point => mp :type => type :opts => opts :dump => dump :pass => pass

Raises:

  • (ArgumentError) 


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# File 'lib/fstab.rb', line 27

def add_entry(opts = {})
  raise ArgumentError.new(":dev key is required (fs_spec).") unless opts[:dev]
  dev = opts[:dev].strip.chomp
  uuid = nil
  label = nil
  case dev
  when /\/dev\// # device path
    pdev = dev
  when /^\/\/\w+(\.\w+)*((\/)|\w+|\.)*/ #smbfs/cifs
  when /^(tmpfs|proc|usbfs|devpts|none|sysfs)/ #special FS
  when /^\w+:\/?\w*(\/\w+)*/ # NFS
  when /[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}/i # UUID
    uuid = dev
  else # Asume FS label, rise exception if FS label does not exist 
    if File.blockdev?("/dev/disk/by-label/#{dev}")
      label = dev
    else
      raise Exception.new "Unsupported filesystem #{dev}" 
    end
  end

  if opts[:mount_point].nil? or opts[:type].nil? or \
     opts[:opts].nil? or opts[:dump].nil? or opts[:pass].nil?
    raise ArgumentError.new("Missing :mount_point, :type, :opts, :dump or :pass options")
  end

  if @safe_mode
    if label 
      raise ArgumentError.new("Invalid device label #{label}") unless \
            File.blockdev?("/dev/disk/by-label/#{opts[:label]}")
      opts[:uuid] = Fstab.get_uuid_from_label(label) 
    elsif uuid
      raise ArgumentError.new("Invalid device UUID #{uuid}") unless \
            File.blockdev?("/dev/disk/by-uuid/#{uuid}")
      opts[:uuid] = uuid
    elsif pdev
      raise ArgumentError.new("Invalid device path #{pdev}") unless \
            File.blockdev?("#{pdev}")
      opts[:uuid] = Fstab.get_uuid(pdev)
    else
      # Asume special device
      special = true
    end
    unless special
      raise ArgumentError.new("Duplicated entry found (safe_mode=on)") if has_device?(dev)
    end
  end

  backup_fstab
  File.open @file, 'w' do |f|
    f.puts @contents
    f.puts format_entry(dev, opts)
  end
end

#add_fs(dev, mpoint, type, opts, dump = 0, pass = 0) ⇒ Object 



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# File 'lib/fstab.rb', line 82

def add_fs(dev, mpoint, type, opts, dump = 0, pass = 0)
  o = {}
  o[:dev] = dev
  o[:mount_point] = mpoint
  o[:type] = type 
  o[:opts] = opts
  o[:dump] = dump
  o[:pass] = pass
  add_entry o
end

#auto_header ⇒ Object 



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# File 'lib/fstab.rb', line 170

def auto_header
  @header ||= "#\n" +
              "# This file was autogenerated at #{Time.now.to_s}\n" +
              "#\n"
end

#entries ⇒ Object 



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# File 'lib/fstab.rb', line 17

def entries
  parse
end

#find_device(dev) ⇒ Object

Accepts UUID/LABEL/dev



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# File 'lib/fstab.rb', line 198

def find_device(dev)
  # get canonical device_name
  begin
    dev = Fstab.get_blockdev(dev)
    parse.each do |k, v|
      return { k => v } if k == dev
    end
  rescue
  end
  nil
end

#has_device?(dev) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fstab.rb', line 210

def has_device?(dev)
  !find_device(dev).nil?
end

#invalid_entries ⇒ Object 



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# File 'lib/fstab.rb', line 191

def invalid_entries 
  Hash[parse.find_all { |k,v| v[:invalid] }]
end

#line_count ⇒ Object 



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# File 'lib/fstab.rb', line 93

def line_count
  @lcount
end

#parse(reload = true) ⇒ Object

Raises:

  • (Exception) 


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# File 'lib/fstab.rb', line 97

def parse(reload = true)
  @contents = File.read @file if reload
  raise Exception.new("/sbin/blkid not found") unless File.exist?('/sbin/blkid')
  fslist = {}
  ucount = 0
  @lcount = 0
  @contents.each_line do |l|
    next if l.strip.chomp.empty?
    @lcount += 1
    next if l =~ /\s*#/
    fs, mp, type, opts, dump, pass = l.split
    
    # FSTAB(5) states that pass and dump are optional, defaults to 0
    pass = "0" unless pass
    dump = "0" unless dump
    pdev = nil
    label = nil
    uuid = nil
    special = false
    if l =~ /^\s*LABEL=/
      # by LABEL
      label = fs.split("=").last.strip.chomp
      pdev = "/dev/" + File.readlink("/dev/disk/by-label/#{label}").split("/").last rescue "unknown_#{ucount}"
      uuid = Fstab.get_uuid pdev
    elsif l =~ /^\s*UUID=/
      # by UUID
      uuid = fs.split("=").last.strip.chomp
      pdev = "/dev/" + File.readlink("/dev/disk/by-uuid/#{uuid}").split("/").last rescue "unknown_#{ucount}"
      label = Fstab.get_label pdev
    elsif l =~ /^\s*\/dev/
      # by dev path
      pdev = fs
      blkid = `/sbin/blkid #{pdev}`
      label = blkid.match(/LABEL="(.*?)"/)[1] rescue nil
      uuid = blkid.match(/UUID="(.*?)"/)[1] rescue nil
    else
      # FIXME: somewhat risky to assume that everything else
      # can be considered a special device, but validating this
      # is really tricky.
      special = true
      pdev = fs
    end
    # Fstab entries not matching real devices have pdev unknown
    invalid = (l.split.count != 6) # invalid entry if < 6 columns
    if (uuid.nil? and label.nil? and !special) or 
       pdev =~ /^unknown_/ or \
       (!File.exist?(pdev) and !special) 
      invalid = true
      ucount += 1
    end

    invalid = true unless (dump =~ /0|1|2/ and pass =~ /0|1|2/)

    fslist[pdev] = { 
      :label => label, 
      :uuid => uuid, 
      :mount_point => mp,
      :type => type, 
      :opts => opts, 
      :dump => dump,
      :pass => pass,
      :special => special,
      :line_number => @lcount,
      :invalid => invalid,
    } 
  end 
  fslist
end

#remove_invalid_entries ⇒ Object

May rise exception



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# File 'lib/fstab.rb', line 179

def remove_invalid_entries
  return false if invalid_entries.empty?
  backup_fstab
  File.open @file, 'w' do |f|
    f.puts auto_header
    valid_entries.each do |k,v|
      f.puts format_entry(k, v)
    end
  end
  true
end

#valid_entries ⇒ Object 



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# File 'lib/fstab.rb', line 166

def valid_entries
  Hash[parse.find_all { |k,v| !v[:invalid] }]
end