From: Jos Backus <jos@...>
Date: 2004-05-08T03:28:59+09:00
Subject: Ruby Installer for Windows: use of Win32OLE bug causes crash

This is with the latest Ruby Installer for Windows, 181-13-rc2.

When I run the script below I see:

C:\localbin>diskspace.rb
(offline mode: enter name=value pairs on standard input)
^Z
(eval):1214: [BUG] Segmentation fault
ruby 1.8.1 (2003-12-25) [i386-mswin32]
   
   
This application has requested the Runtime to terminate it in an unusual
way.
Please contact the application's support team for more information.
   
C:\localbin>

When I replace the get_diskinfo call with a call to fake_get_diskinfo,
skipping the Win32OLE calls, the program works fine (but is useless, of
course). I have added a comment to (closed) bug 522 on RubyForge.

Any help is appreciated.

#!ruby

require 'win32ole'
require 'cgi'
require 'stringio'

outputfilename = "diskspace.htm"

hosts = []
File.open("diskspace_hosts.txt").each_line do |line|
  next if line =~ /^\s*(#|$)/
  hosts << line.chomp
end

hosts =%w(localhost localhost localhost somehost)

class DiskInfo
  attr_reader :deviceid, :size, :freespace
  def initialize(deviceid, size, freespace)
     @deviceid, @size, @freespace = deviceid, size.to_i, freespace.to_i
  end
  def pct_free
     freespace.to_f / size * 100
  end
end

def fake_get_diskinfo(host)
  result = []
  result << DiskInfo.new('C:', 10000000000, 5000000000)
  result << DiskInfo.new('D:', 20000000000, 8000000000)
end

# Returns a list of DiskInfo objects for host, or nil
def get_diskinfo(host)
  result = []
  begin
    wmi = WIN32OLE.connect("winmgmts://#{host}/root/cimv2")
  rescue
    return nil
  end
  disks = wmi.ExecQuery("Select * from Win32_LogicalDisk")
  disks.each do |disk|
    next if disk.Size.nil?
    result << DiskInfo.new(disk.DeviceID, disk.Size, disk.FreeSpace)
  end
  result
end

# Map freespace percentage to color codes 
def alert_color(value)
   case value
   when 20..100; "lightgreen"
   when 10...20;  "yellow"
   when 5...10;   "orange"
   when 0...5;     "red"
   else raise # Shouldn't happen 
   end
end

diskdata = hosts.collect do |host|
  [ host, get_diskinfo(host) ]
end

File.open(outputfilename, "w") do |file|
  # Hack alert:
  # Since cgi.out writes to $DEFAULT_OUTPUT we capture the output in outstring by directing $DEFAULT_OUTPUT to it.
  # We need to do this because we want to strip the first 3 lines from the output (the HTTP header).
  outstring = StringIO.new
  $DEFAULT_OUTPUT = outstring

  cgi = CGI.new("html4")  # add HTML generation methods
  cgi.out {
     cgi.html {
        cgi.head { "\n" + cgi.title{"Disk Space Overview"} } +
        cgi.body { "\n" +
           cgi.h2 { "Disk space by host by drive" } +
	   cgi.p { "Last updated: " + Time.now.to_s } +
           cgi.table {
              cgi.tr { cgi.th({"width" => "120%", "align" => "left"}) { "Host" } + cgi.th { "Disk" } + cgi.th { "Total" } + cgi.th { "Free" } + cgi.th { "%" } } +
	      diskdata.collect do |host, di|
	      unless di
		  cgi.tr { cgi.td("bgcolor" => "red") { host } }
	      else
		 di.collect { |disk|
                    cgi.tr {
                               cgi.td { host } +
			       cgi.td { disk.deviceid } +
			       cgi.td { disk.size / 1024 ** 3 } +
			       cgi.td { disk.freespace / 1024 ** 3 } +
			       cgi.td("bgcolor" => alert_color(disk.pct_free)) { "%3.2d" % disk.pct_free }
                     }
                   }
		end
	      end.join("\n")
           }
        }
     }
  }
  
  outstring.rewind
  file.puts outstring.readlines[3..-1] # Drop HTTP header
  outstring.close
end

exit

-- 
Jos Backus                       _/  _/_/_/      Sunnyvale, CA
                                _/  _/   _/
                               _/  _/_/_/
                          _/  _/  _/    _/
jos at catnook.com        _/_/   _/_/_/          require 'std/disclaimer'