#
# Author:: Phil Dibowitz <phil@ipom.com>
# Author:: Adam Jacob <adam@chef.io>
# Copyright:: Copyright (c) 2008-2017 Chef Software, Inc.
# Copyright:: Copyright (c) 2015 Facebook, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

Ohai.plugin(:Filesystem) do
  provides "filesystem"

  def find_device(name)
    %w{/dev /dev/mapper}.each do |dir|
      path = File.join(dir, name)
      return path if File.exist?(path)
    end
    name
  end

  def parse_line(line, cmdtype)
    case cmdtype
    when "lsblk"
      regex = /NAME="(\S+).*?" UUID="(\S*)" LABEL="(\S*)" FSTYPE="(\S*)"/
      if line =~ regex
        dev = $1
        dev = find_device(dev) unless dev.start_with?("/")
        uuid = $2
        label = $3
        fs_type = $4
        return { :dev => dev, :uuid => uuid, :label => label, :fs_type => fs_type }
      end
    when "blkid"
      bits = line.split
      dev = bits.shift.split(":")[0]
      f = { :dev => dev }
      bits.each do |keyval|
        if keyval =~ /(\S+)="(\S+)"/
          key = $1.downcase.to_sym
          key = :fs_type if key == :type
          f[key] = $2
        end
      end
      return f
    end
    nil
  end

  def generate_device_view(fs)
    view = {}
    fs.each_value do |entry|
      view[entry[:device]] = Mash.new unless view[entry[:device]]
      entry.each do |key, val|
        next if %w{device mount}.include?(key)
        view[entry[:device]][key] = val
      end
      view[entry[:device]][:mounts] ||= []
      if entry[:mount]
        view[entry[:device]][:mounts] << entry[:mount]
      end
    end
    view
  end

  def generate_mountpoint_view(fs)
    view = {}
    fs.each_value do |entry|
      next unless entry[:mount]
      view[entry[:mount]] = Mash.new unless view[entry[:mount]]
      entry.each do |key, val|
        next if %w{mount device}.include?(key)
        view[entry[:mount]][key] = val
      end
      view[entry[:mount]][:devices] ||= []
      if entry[:device]
        view[entry[:mount]][:devices] << entry[:device]
      end
    end
    view
  end

  collect_data(:linux) do
    fs = Mash.new

    # Grab filesystem data from df
    begin
      so = shell_out("df -P")
      so.stdout.each_line do |line|
        case line
        when /^Filesystem\s+1024-blocks/
          next
        when /^(.+?)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+\%)\s+(.+)$/
          key = "#{$1},#{$6}"
          fs[key] = Mash.new
          fs[key][:device] = $1
          fs[key][:kb_size] = $2
          fs[key][:kb_used] = $3
          fs[key][:kb_available] = $4
          fs[key][:percent_used] = $5
          fs[key][:mount] = $6
        end
      end

      # Grab filesystem inode data from df
      so = shell_out("df -iP")
      so.stdout.each_line do |line|
        case line
        when /^Filesystem\s+Inodes/
          next
        when /^(.+?)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+\%)\s+(.+)$/
          key = "#{$1},#{$6}"
          fs[key] ||= Mash.new
          fs[key][:device] = $1
          fs[key][:total_inodes] = $2
          fs[key][:inodes_used] = $3
          fs[key][:inodes_available] = $4
          fs[key][:inodes_percent_used] = $5
          fs[key][:mount] = $6
        end
      end
    rescue Ohai::Exceptions::Exec => e
      unless Ohai.config[:plugin][:filesystem][:allow_partial_data]
        raise e
      end
      logger.warn("Plugin Filesystem: df binary is not available. Some data will not be available.")
    end

    # Grab mount information from /bin/mount
    begin
      so = shell_out("mount")
      so.stdout.each_line do |line|
        if line =~ /^(.+?) on (.+?) type (.+?) \((.+?)\)$/
          key = "#{$1},#{$2}"
          fs[key] = Mash.new unless fs.has_key?(key)
          fs[key][:device] = $1
          fs[key][:mount] = $2
          fs[key][:fs_type] = $3
          fs[key][:mount_options] = $4.split(",")
        end
      end
    rescue Ohai::Exceptions::Exec
      unless Ohai.config[:plugin][:filesystem][:allow_partial_data]
        raise e
      end
      logger.warn("Plugin Filesystem: mount binary is not available. Some data will not be available.")
    end

    # We used to try to decide if we wanted to run lsblk or blkid
    # but they each have a variety of cases were they fail to report
    # data. For example, there are a variety of cases where lsblk won't
    # report unmounted filesystems, but blkid will. And vise-versa. Sweet.
    # So for reliability, we'll run both, if we have them.

    lsblk = which("lsblk")
    blkid = which("blkid")
    cmds = []
    # These should be in order of preference... first writer wins.
    if lsblk
      cmds << "#{lsblk} -n -P -o NAME,UUID,LABEL,FSTYPE"
    end
    if blkid
      cmds << blkid
    end

    cmds.each do |cmd|
      cmdtype = File.basename(cmd.split.first)
      # setting the timeout here for `lsblk` and `blkid` commands to 60
      # this is to allow machines with large amounts of attached LUNs
      # to respond back to the command successfully
      so = shell_out(cmd, timeout: 60)
      so.stdout.each_line do |line|
        parsed = parse_line(line, cmdtype)
        next if parsed.nil?
        # lsblk lists each device once, so we need to update all entries
        # in the hash that are related to this device
        keys_to_update = []
        fs.each_key do |key|
          keys_to_update << key if key.start_with?("#{parsed[:dev]},")
        end

        if keys_to_update.empty?
          key = "#{parsed[:dev]},"
          fs[key] = Mash.new
          fs[key][:device] = parsed[:dev]
          keys_to_update << key
        end

        keys_to_update.each do |k|
          [:fs_type, :uuid, :label].each do |subkey|
            if parsed[subkey] && !parsed[subkey].empty?
              fs[k][subkey] = parsed[subkey]
            end
          end
        end
      end
    end

    # Grab any missing mount information from /proc/mounts
    if File.exist?("/proc/mounts")
      mounts = ""
      # Due to https://tickets.opscode.com/browse/OHAI-196
      # we have to non-block read dev files. Ew.
      f = File.open("/proc/mounts")
      loop do
        begin
          data = f.read_nonblock(4096)
          mounts << data
        # We should just catch EOFError, but the kernel had a period of
        # bugginess with reading virtual files, so we're being extra
        # cautious here, catching all exceptions, and then we'll read
        # whatever data we might have
        rescue Exception
          break
        end
      end
      f.close
      mounts.each_line do |line|
        if line =~ /^(\S+) (\S+) (\S+) (\S+) \S+ \S+$/
          key = "#{$1},#{$2}"
          next if fs.has_key?(key)
          fs[key] = Mash.new
          fs[key][:device] = $1
          fs[key][:mount] = $2
          fs[key][:fs_type] = $3
          fs[key][:mount_options] = $4.split(",")
        end
      end
    end

    by_pair = fs
    by_device = generate_device_view(fs)
    by_mountpoint = generate_mountpoint_view(fs)

    fs_data = Mash.new
    fs_data["by_device"] = by_device
    fs_data["by_mountpoint"] = by_mountpoint
    fs_data["by_pair"] = by_pair

    # Set the filesystem data
    filesystem fs_data
  end
end