From: Jos Backus <jos@...>
Date: 2004-07-13T13:14:11+09:00
Subject: win32api: how to access NetFileEnum results?

I'm trying to programmatically determine any network opened files on a Windows
2003 Server system using the NETAPI32.NetFileEnum API.

    http://msdn.microsoft.com/library/default.asp?url=/library/en-us/netmgmt/netmgmt/netfileenum.asp

describes this API as

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

My code looks like this:

    require "Win32API"

    MAX_PREFERRED_LENGTH = -1
    level = 3
    entriesread = "\0" * 4
    totalentries = "\0" * 4
    resume_handle = "\0" * 4

    NetFileEnum = Win32API.new("netapi32", "NetFileEnum", 'PPPNPNPPP', 'I')
    ret = NetFileEnum.call(0,0,0,level,bufptr,MAX_PREFERRED_LENGTH,entriesread,totalentries,resume_handle)

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

    rbuf = "\0" * 10240 # testing, should be *entriesread * sizeof(FILE_INFO_3)
    memcpy = Win32API.new('msvcrt','memcpy','PPL','P')
    memcpy.call(rbuf,bufptr,rbuf.size)

    p rbuf

When level == 3, rbuf will contain an array of FILE_INFO_3 structures as
described in

    http://msdn.microsoft.com/library/default.asp?url=/library/en-us/netmgmt/netmgmt/file_info_3_str.asp

which looks like this:

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

My problem is that although the NetFileEnum.call succeeds, *bufstr aka rbuf
doesn't appear to have the expected contents, i.e. the fi3_id value(s) seen
don't correspond with those returned by the `net file' command. The result is
consistent though, leading me to believe I'm either using the wrong parameter
template or misinterpreting rbuf.

What could I be doing wrong?

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