#!/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', 'PPPPPNPPP','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 "NetFileEnum failed: #{ret}"
  exit 2
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