Trying to modify the below script to allow me to query remote
machines. The first parameter to NetFileEnum needs to be a char * to
the machine name. Can't seem to work out how to do that in ruby.

Thanks,
RC

Subject: Re: win32api: how to access NetFileEnum results?
From: Jos Backus <jos catnook.com>
Date: Wed, 14 Jul 2004 09:28:13 +0900
References: 106163 106180 106240 106266
In-reply-to: 106266

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On Wed, Jul 14, 2004 at 04:57:21AM +0900, daz wrote:
> Re-reading the API suggests a change of tack.
> I think that memcpy isn't required.
[snip]
> p rbuf
> #----------------------------------
>
> Good or bad ?

This yields 10k worth of zeroes on my screen :) I think I understand what you
are trying to do (have win32api follow the pointer automagically) but I can't
seem to get it to work. bufptr does have the right value in this case too, so
that part works fine, but I opted to use the simpler initialization instead.
So I ended up doing some memcpy's which I need anyway to access the pathname
and username fields in the returned FILE_INFO_3 structs. The attached code
works for me; cleanup suggestions welcomed!

Thanks for your help guys.

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

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#!/usr/bin/env ruby

# LMSTR =
# LPBYTE* = P
# DWORD = L
# LPDWORD = P
# PDWORD_PTR = L

# NET_API_STATUS NetFileEnum(
#  LMSTR servername,
#  LMSTR basepath,
#  LMSTR username,
#  DWORD level,
#  LPBYTE* bufptr,
#  DWORD prefmaxlen,
#  LPDWORD entriesread,
#  LPDWORD totalentries,
#  PDWORD_PTR resume_handle
#);

# typedef struct _FILE_INFO_3 {
#   DWORD fi3_id;
#   DWORD fi3_permissions;
#   DWORD fi3_num_locks;
#   LMSTR fi3_pathname;
#   LMSTR fi3_username;
# } FILE_INFO_3;

require "Win32API"

NetFileEnum = Win32API.new('netapi32', 'NetFileEnum', 'PPPNPNPPP','I')
Memcpy      = Win32API.new('msvcrt', 'memcpy', 'PPL', 'P')
Pmemcpy1    = Win32API.new('msvcrt', 'memcpy', 'PLL', 'L')
Pmemcpy2    = Win32API.new('msvcrt', 'memcpy', 'LPL', 'L')
Wcslen      = Win32API.new('msvcrt', 'wcslen', 'P', 'L')

class OpenFile
  attr_reader :id, :permissions, :num_locks, :pathname, :username
  def initialize(id, permissions, num_locks, p_pathname, p_username)
    @id, @permissions, @num_locks = id, permissions, num_locks
    pathlen = Wcslen.call(p_pathname) * 2
    userlen = Wcslen.call(p_username) * 2
    pname = "\0" * pathlen
    uname = "\0" * userlen
    Pmemcpy1.call(pname, p_pathname, pathlen)
    Pmemcpy1.call(uname, p_username, userlen)
    @pathname = pname.delete("\0")
    @username = uname.delete("\0")
  end
  def inspect
    "File #{@pathname} opened by #{@username} (id #{@id},
#{@num_locks} lock(s))"
  end
end

MAX_PREFERRED_LENGTH = -1
FILE_INFO_3_SIZE = 20
LEVEL = 3

bufptr = "\0" * 4
entriesread = "\0" * 4
totalentries = "\0" * 4
resume_handle = "\0" * 4

ret = NetFileEnum.call(nil, nil, nil, LEVEL, bufptr, MAX_PREFERRED_LENGTH,
    entriesread, totalentries, resume_handle)

if 0 != ret
  puts "Failed: #{ret}"
  exit
end

entriesread = entriesread.unpack("S")[0]
totalentries = totalentries.unpack("S")[0]

rbuf = "\0" * entriesread * FILE_INFO_3_SIZE

# bufptr now contains a ptr to a ptr
Pmemcpy1.call(rbuf, bufptr.unpack("L")[0], entriesread * FILE_INFO_3_SIZE)

open_files = []
entriesread.times do |i|
  open_files << OpenFile.new(*rbuf[i * FILE_INFO_3_SIZE,
FILE_INFO_3_SIZE].unpack("LLLLL"))
end

open_files.each do |file|
  p file
end

exit