windows page 10 - Dave's Blog

IPv6 Roundup: Address Syntax on Windows

2008 Jan 9, 11:34

IPv6 address syntax consists of 8 groupings of colon delimited 16-bit hex values making up the 128-bit address. An optional double colon can replace any consecutive sequence of 0 valued hex values. For example the following is a valid IPv6 address: fe80::2c02:db79

Some IPv6 addresses aren't global and in those cases need a scope ID to describe their context. These get a '%' followed by the scope ID. For example the previous example with a scope ID of '8' would be: fe80::2c02:db79%8

IPv6 addresses in URIs may appear in the host section of a URI as long as they're enclosed by square brackets. For example: http://[fe80::2c02:db79]/. The RFC explicitly notes that there isn't a way to add a scope ID to the IPv6 address in a URI. However a draft document describes adding scope IDs to IPv6 addresses in URIs. The draft document uses the IPvFuture production from the URI RFC with a 'v1' to add a new hostname syntax and a '+' instead of a '%' for delimiting the scope id. For example: http://[v1.fe80::2c02:db79+8]/. However, this is still a draft document, not a final standard, and I don't know of any system that works this way.

In Windows XPSP2 the IPv6 stack is available but disabled by default. To enable the IPv6 stack, at a command prompt run 'netsh interface ipv6 install'. In Vista IPv6 is the on by default and cannot be turned off, while the IPv4 stack is optional and may be turned off by a command similar to the previous.

Once you have IPv6 on in your OS you can turn on IPv6 for IIS6 or just use IIS7. The address ::1 refers to the local machine.

In some places in Windows like UNC paths, IPv6 addresses aren't allowed. In those cases you can use a Vista DNS IPv6 hack that lives in the OS name resolution stack that transforms particularly crafted names into IPv6 addresses. Take your IPv6 address, replace the ':'s with '-'s and the '%' with an 's' and then append '.ipv6-literal.net' to the end. For example: fe80--2c02-db79s8.ipv6-literal.net. That name will resolve to the same example I've been using in Vista. This transformation occurs inside the system's local name resolution stack so no DNS servers are involved, although Microsoft does own the ipv6-literal.net domain name.

MSDN describes IPv6 addresses in URIs in Windows and I've described IPv6 addresses in URIs in IE7. File URIs in IE7 don't support IPv6 addresses. If you want to put a scope ID in a URI in IE7 you use a '%25' to delimit the scope ID and due to a bug you must have at least two digits in your scope ID. So, to take the previous example: http://[fe80::2c02:db79%2508]/. Note that its 08 rather than just 8.

roundup ip windows ipv6 technical microsoft boring syntax

Windows Media Center and Zune Integration Hack

2007 Nov 28, 1:23One of the new Zune features that had me the most excited was the claimed improved Windows Media Center integration which unfortunately turned out to simply mean support for the Win MCE video format (with an exception for HD). I wanted to be able to pick shows recorded by my Win MCE and have the Zune automatically sync up the latest episodes. However, with the improved podcast support in the Zune software one can easily create a ridiculous hack to accomplish this.

The new Zune software has podcast support which does everything I'd want to do with a Win MCE recorded TV series so the goal is to shoehorn a TV series into a Zune podcast. An overview of the steps: Create an XSLT that converts Win MCE data to a podcast, run the XSLT as a scheduled task every few hours per TV series, setup a Web server pointed at the resulting podcasts and the Win MCE Recorded TV directory, and subscribe to the resulting podcasts in the Zune software.

1. Reading through the Win MCE data stored as an XML file in "C:\ProgramData\Microsoft\eHome\Recording\Recordings.xml" and the spec for podcasts I created an XSLT to convert a series from Win MCE data to a podcast.
2. I added a new task to the Scheduled Tasks to run my XSLT using my xsltproc.js script. The task runs a handful of commands that look something like the following:

   C:\windows\system32\wscript.exe C:\users\dave\bin\xsltproc.js C:\Users\Dave\Documents\trunk\development\mce-zune\mce-to-podcast.xslt C:\ProgramData\Microsoft\eHome\Recording\Recordings.xml --param title "The Daily Show With Jon Stewart" --param max 4 --param baseURI "http://groucho/" --param thisRelURI "tds.xml" -o "D:\recorded tv\tds.xml"

   For each TV series I run a command like the above and that outputs a podcast for that series into my "D:\Recorded TV\" directory.
3. Zune only allows http URIs for its podcasts so I installed a web server on my Win MCE server. I'm running Vista Ultimate so it was quick and easy for me to install IIS7 but any Web server will do. Then I pointed it at "D:\Recorded TV\".
4. Once all the above was done I just subscribed to the resulting podcasts via my Web server and viola! Since I'm forced to use a Web server I can even run the Zune software on a machine other than my Win MCE server. You can see a screen-shot above of my Zune software showing my Colbert Report podcast.

technical xml mce hack windows media center zune windows xslt podcast

IEBlog: URI Comparison Functions

2007 Oct 24, 6:20I have a new post on the IE Blog on the topic of Win32 URI Comparison Functions.
I've blogged there previously on the topics of IPv6 URIs in IE7, International Mailto URIs in IE7, File URIs in Windows, and CreateURLMoniker Considered Harmful. Hooray for URIs!microsoft technical blog url win32 ie windows uri

XSL Transforms in JavaScript

2007 Oct 7, 4:12In a previous post I mentioned an xsltproc like js file I made. As noted in that post, on Windows you can write console script files in JavaScript, name them foo.js, and execute them from the command prompt. I later found that MSDN has an XSLT javascript sample which looks similar to mine, but I like mine better for the XSLT parameter support and having a non-ridiculous way of interpreting filenames. The code for my xsltproc.js follows. The script is very simple and demonstrates the ease with which you can manipulate these system objects and all it takes is opening up notepad.

var createNewXMLObj = function() {
   var result = new ActiveXObject("MSXML2.FreeThreadedDOMDocument");
   result.validateOnParse = false;
   result.async = false;
   return result;
}

var args = WScript.arguments;
var ofs = WScript.CreateObject("Scripting.FileSystemObject");

var xslParams = [];
var xmlStyle = null;
var xmlInput = null;
var inputFile = null;
var outputFile = null;
var error = false;

for (var idx = 0; idx < args.length && !error; ++idx)
   if (args.item(idx) == "-o") {
      if (idx + 1 < args.length) {
         outputFile = ofs.GetAbsolutePathName(args.item(idx + 1));
         ++idx;
      }
      else
         error = true;
   }
   else if (args.item(idx) == "--param" || args.item(idx) == "-param") {
      if (idx + 2 < args.length) {
         xslParams[args.item(idx + 1)] = args.item(idx + 2);
         idx += 2;
      }
      else
         error = true;
   }
   else if (xmlStyle == null) {
      xmlStyle = createNewXMLObj();
      xmlStyle.load(ofs.GetAbsolutePathName(args.item(idx)));
   }
   else if (xmlInput == null) {
      inputFile = ofs.GetAbsolutePathName(args.item(idx));
      xmlInput = createNewXMLObj();
      xmlInput.load(inputFile);
   }

if (xmlStyle == null || xmlInput == null || error) {
   WScript.Echo('Usage:\n\t"xsltproc" xsl-stylesheet input-file\n\t\t["-o" output-file] *["--param" name value]');
}
else {
   var xslt = new ActiveXObject("MSXML2.XSLTemplate.3.0");
   xslt.stylesheet = xmlStyle;
   var xslProc = xslt.createProcessor();
   xslProc.input = xmlInput;

   for (var keyVar in xslParams)
      xslProc.addParameter(keyVar, xslParams[keyVar]);

   xslProc.transform();

   if (outputFile == null)
      WScript.Echo(xslProc.output);
   else {
      var xmlOutput = createNewXMLObj();
      xmlOutput.loadXML(xslProc.output);
      xmlOutput.save(outputFile);
   }
}

js xml jscript windows xslt technical xsltproc wscript xsl javascript

Which which - Batch File Hackiness

2007 Aug 9, 5:41To satisfy my hands which have already learned to type *nix commands I like to install Win32 versions of common GNU utilities. Unfortunately, the which command is a rather literal port and requires you to enter the entire name of the command for which you're looking. That is 'which which' won't find itself but 'which which.exe' will. This makes this almost useless for me so I thought to write my own as a batch file. I had learned about a few goodies available in cmd.exe that I thought would make this an easy task. It turned out to be more difficult than I thought.

for /F "usebackq tokens=*" %%a in ( `"echo %PATH:;=& echo %"` ) do (
    for /F "usebackq tokens=*" %%b in ( `"echo %PATHEXT:;=& echo %"` ) do (
        if exist "%%a"\%1%%b (
            for  %%c in ( "%%a"\%1%%b ) do (
                echo %%~fc
            )
        )
    )
)

The environment variables PATH and PATHEXT hold the list of paths to search through to find commands, and the extensions of files that should be run as commands respectively. The 'for /F "usebackq tokens=*" %%a in (...) do (...)' runs the 'do' portion with %%a sequentially taking on the value of every line in the 'in' portion. That's nice, but PATH and PATHEXT don't have their elements on different lines and I don't know of a way to escape a newline character to appear in a batch file. In order to get the PATH and PATHEXT's elements onto different lines I used the %ENV:a=b% syntax which replaces occurrences of a with b in the value of ENV. I replaced the ';' delimiter with the text '& echo ' which means %PATHEXT:;=& echo% evaluates to something like "echo .COM& echo .EXE& echo .BAT& ...". I have to put the whole expression in double quotes in order to escape the '&' for appearing in the batch file. The usebackq and the backwards quotes means that the backquoted string should be replaced with the output of the execution of its content. So in that fashion I'm able to get each element of the env. variable onto new lines. The rest is pretty straight forward.

Also, it supports wildcards:

C:\Users\davris>which.cmd *hi*
C:\Windows\System32\GRAPHICS.COM
C:\Windows\System32\SearchIndexer.exe
D:\bin\which.exe
D:\bin\which.cmd

which cmd technical batch for

Two-for Script File

2007 Aug 6, 5:40I was messing with the XSLT to XSL Converter source which is a javascript file that can be run with cscript.exe. I've changed it to be like a very basic version of xsltproc that simply runs an XML file through an XSLT. I also wanted to run this from the command prompt without writing "cscript ..." everytime. I decided to make like perl programmers I've seen and make a JS file that works as a batch file and a JS file at the same time.

Here's a basic version of what I ended doing applied to a 'hello world' script named helloworld.cmd:

/* 2> NUL
@echo off
cscript /e:javascript /nologo "%~f0" %*
@goto :eof

    Hello World
        Says 'Hello world.' when you run it.
*/

var outText = 'Hello world.';
WScript.Echo(outText);

Running this on a command prompt gives the following:

C:\Users\davris>helloworld

C:\Users\davris>/*  2>NUL
Hello world.

However, after a little more experimentation I found this was slightly overkill for my purposes since if I rename the file to helloworld.js and just type its name like a command it is run by cscript:

C:\Users\davris>helloworld
Microsoft (R) Windows Script Host Version 5.7
Copyright (C) Microsoft Corporation. All rights reserved.

Hello world.

So this time I didn't need all that but if ever in the future I need to run a batch file then a JS file I can do it with one file...cmd js technical cscript batch xslt xsl javascript

Wp64 Issues

2007 Aug 6, 3:43Miladin told me about the Visual Studio compiler's promising option Wp64 that finds 64bit portability issues when compiling in 32bit. If, for instance, you cast from a (long*) to a (long) you get a W4 warning. However, the #defines are still set for 32bit builds. This means that other parts of the code can make assumptions based on the #defines that are valid on 32bit but generate 64bit errors or warnings.

For instance, in winuser.h the public published Windows header file there's the following:

...
#ifdef _WIN64
...
WINUSERAPI
LONG_PTR
WINAPI
SetWindowLongPtrA(
    __in HWND hWnd,
    __in int nIndex,
    __in LONG_PTR dwNewLong);
...
#else  /* _WIN64 */
...
#define SetWindowLongPtrA   SetWindowLongA
...
#endif /* _WIN64 */
...

In 64bit everything's normal but in 32bit SetWindowLongPtrA is #defined to SetWindowLongA which takes a LONG rather than a LONG_PTR. So take the following code snippet:

...
LONG_PTR inputValue = 0;
LONG_PTR error = SetWindowLongPtrA(hWnd, nIndex, inputValue);
...

This looks fine but generates warnings with the Wp64 flag.

In 64 bit, p is cast to (LONG_PTR) and that's great because we're actually calling SetWindowLongPtrA which takes a LONG_PTR. In 32 bit, p is cast to (LONG_PTR) which is then implicitly cast to (LONG) because we're actually calling SetWindowLongA. LONG and LONG_PTR are the same size in 32bit which is fine but if you turn on the Wp64 flag there's a W4 warning because of the implicit cast from a larger size to a smaller size if you were to compile for 64bit. So even though doing a 32bit or 64bit compile would have worked just fine, if you turn on the Wp64 flag for 32bit you'd get an error here.

It looks like I'm the most recent in a list of people to notice this issue. Well I investigated this so... I'm blogging about it too!wp64 technical 64bit compiler c++ visual-studio setwindowlongptra