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WinDbg Commands

Posted in .NET | Debugging at Saturday, July 24, 2010 10:45 PM W. Europe Daylight Time

I just finished watching Ingo Rammer’s sessions on debugging from NDC 2010:

While I consider myself experienced in debugging with Visual Studio I still didn’t know the Ctrl+B trick Ingo shows in the first session to create breakpoint groups, for example to break on all methods named WriteLine.

Ingo’s second session goes into detail how to start with WinDbg. During his talk Ingo wrote down quite a lot of WinDbg commands that I copied and extended a bit for my own reference.

# Use debugger according to architecture that is being debugged.

# Drag exe onto WinDbg to start debugging.

# Debugging services:
# 1. Using Global Flags
#  - On "Image File" tab, enter service exe
#  - Set debugger to cdb.exe -server tcp:port=1234
# 2. Start service
# 3. Start WinDbg
#  - connect to remote session: tcp:server=localhost,port=1234
# Also works (unsecured) over networks


.loadby sos mscorwks # CLR 2
.loadby sos clr      # CLR 4, both after the debuggee has loaded the CLR
.chain               # Shows loaded extensions

sxe <event code> # Stop
sxn <event code> # Notify
sxi <event code> # Ignore
# ... on <event code> exceptions (for example, <event code> = clr)

g            # Go
.cls         # Clear screen

!pe          # Print exception
!clrstack    # Display stack trace
!clrstack -a # Stack trace with additional information (parameters and locals)
# If there is no stack information the JIT optimized the code away (i.e. inlining).
!dumpstack   # Another way to get the stack trace

!u <address> # Unassemble code at <address>
# Look for calls into managed code (to the right) to find the line/call that caused the exception.
# <assembly>_ni = Native image

!do <address> # Dump object
!da <address> # Dump array
# To copy addresses: Left double-click a numeric value, double right-click to copy it to the command line.

~            # Show all (managed and unmanaged) threads
!threads     # Show managed threads
~2s          # Switch to thread 2 (#2 in the unnamed column)
!runaway     # Show thread execution times (user-mode) - to find hanging threads

!dumpheap    # Show heap information, 1 line per instance
!dumpheap -stat # Heap statistics, most memory-consuming at the bottom. MT = class "pointer"
!dumpheap -stat -type TextBox # Show instances of classes containing "TextBox"
!dumpheap -type TextBox
!dumpheap -mt <type> # Dumps all instances of "TextBox" or <type>
!gcroot <address> # Why is the instance at <address> in memory?
# Domain = new GC root that reference <address> (~ static instance)
# Ignore WeakReferences, look for (pinned) references

# Create dumps from code:
[DllImport("DbgHelp.dll", SetLastError = true]
static extern bool MiniDumpWriteDump(
    IntPtr hProcess,
    int processId,
    IntPtr fileHandle,
    int dumpType, // 0x0 or 0x6 for managed code
    IntPtr exceptionInfo,
    IntPtr userInfo,
    IntPtr extInfo);

Visual Studio Tip: Setting Indent Width and Tabs/Spaces Quickly Using Macros

Posted in .NET | Presentations | Visual Studio at Sunday, January 24, 2010 5:07 PM W. Europe Standard Time

Over the last years I’ve been contributing to several Open Source software projects, just to name the most recent:

All of the above projects follow their own style how to lay out the source code using indents. It seems like everybody has a different opinion you would have to cater for, for example:

  • Indenting is done with tabs
  • 4-space indents
  • 2-space indents

Often times these conventions are implicit, you have to read the source code to see the actual style the authors follow. It is encouraged to apply these guidelines to your patches ensure they will be accepted.

I often switch between developing for projects, so before writing a single line of code I have to hit Visual Studio’s Tools | Options | Text Editor Options dialog and change the indent settings to match the project’s conventions.

Visual Studio Text Editor Options

This has become very tedious, additionally, I often forget to adjust the indent settings before writing code. (Perhaps I forget it because it’s so annoying.)

To scratch that itch I sat down and wrote some Visual Studio macros that apply the most commonly used settings:

Imports System
Imports EnvDTE
Imports EnvDTE80
Imports EnvDTE90
Imports System.Diagnostics

Public Module Fonts
    Sub TwoSpaces()
        Dim textEditor As Properties

        textEditor = DTE.Properties("TextEditor", "AllLanguages")
        textEditor.Item("IndentStyle").Value = vsIndentStyle.vsIndentStyleSmart
        textEditor.Item("TabSize").Value = 4
        textEditor.Item("IndentSize").Value = 2
        textEditor.Item("InsertTabs").Value = False
    End Sub

    Sub FourSpaces()
        Dim textEditor As Properties

        textEditor = DTE.Properties("TextEditor", "AllLanguages")
        textEditor.Item("IndentStyle").Value = vsIndentStyle.vsIndentStyleSmart
        textEditor.Item("TabSize").Value = 4
        textEditor.Item("IndentSize").Value = 4
        textEditor.Item("InsertTabs").Value = False
    End Sub

    Sub OneTab()
        Dim textEditor As Properties

        textEditor = DTE.Properties("TextEditor", "AllLanguages")
        textEditor.Item("IndentStyle").Value = vsIndentStyle.vsIndentStyleSmart
        textEditor.Item("TabSize").Value = 4
        textEditor.Item("IndentSize").Value = 4
        textEditor.Item("InsertTabs").Value = True
    End Sub

    Public Sub NormalFonts()
    End Sub

    Public Sub LargeFonts()
    End Sub

    Sub SetFontSize(ByVal size As Int32)
        Dim textEditor As Properties

        textEditor = DTE.Properties("FontsAndColors", "TextEditor")
        textEditor.Item("FontSize").Value = size
    End Sub
End Module

These macros are associated with toolbar buttons:

Visual Studio Toolbar Buttons

The first two buttons are associated to the LargeFonts and NormalFonts macros that set the editor font size. I like to invoke these when doing presentations. No more fiddling with Tools | Options to ensure your audience is able to read the code on the wall.

The last three buttons should be self-explaining, they’re to quickly set tabbed, two-space and four-space indents, respectively.

Using the Microsoft Solver Foundation Add-In for Excel

Posted in .NET | Debugging | Office at Sunday, January 17, 2010 3:52 PM W. Europe Standard Time

After listening to the Hanselminutes episode on Microsoft Solver Foundation (MSF) I decided it’s time to give it a shot today. Solver Foundation seems to be a solution to a set of constrained problems I sometimes face:

  • Sharing costs and calculating minimal money transfers after trips with my friends, where each friend spent some money.
  • Giving out questions to attendees of our User Group “Boot Camps”: Speakers prepare ~20 questions, ranging from easy to moderate levels. We assign each attendee an easy question and one to chew a bit upon. Further, every question should be given out to two attendees, so in case someone doesn’t make it to the meeting we’re still able to cover the question.

Something I don’t remember Scott Hanselman and his guest talking about is that Solver Foundation comes with an Excel Add-In that is supposed to make creating models easy easier, no code needed. Along with the “Solver Foundation for Excel Primer” document that is installed along with the binaries I figured Excel would be a good way to start looking into Solver Foundation.

After the MSI ran, I started Excel but didn’t find the Solver Foundation tab that’s advertised in the primer. The COM Add-Ins dialog said something about that the Add-In could not be loaded. Nice! Luckily the Event Viewer was more helpful in terms of error messages where I found this beauty of an exception:

Customization could not be loaded because the application domain could not be created.
---> System.IO.FileLoadException: Could not load file or assembly 'MicrosoftSolverFoundationForExcel, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies.
The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

My first guess was that an old MSF assembly was referenced and I decided to go with an assembly binding redirect for excel.exe. Didn’t help. The next step was to get into the innards of VSTO deployment. What I found in the MicrosoftSolverFoundationForExcel.vsto and MicrosoftSolverFoundationForExcel.dll.manifest files wasn’t surpising: Several references to old versions of MSF. None of which were deployed by the MSI installer, so Excel trying to load such dependencies failed.

<assemblyIdentity name="MicrosoftSolverFoundationForExcel" version=""…
<assemblyIdentity name="MicrosoftSolverFoundationForExcel" version=""…

I updated both references to the match the installed version, just to find myself faced with another error saying that the manifest’s digital signature is broken.

Now was time to contact my friend Lars Keller who is an expert in VSTO development. Lars told me that I would have to re-sign the .vsto and .manifest files to make the signature reflect my changes. The Office Development with Visual Studio blog has the full details.

  1. I had to create a certificate that can be used for code signing:
    makecert -r -pe -n "CN=Your Name" -b 01/01/2010 -e 01/01/2099 -eku -ss My
  2. Export the certificate as a PFX file using certmgr.msc
  3. Create a backup copy of the MSF Excel Add-In .manifest and .vsto files
  4. Open a Visual Studio Command prompt and navigate to the manifest's location
  5. Make edits to the manifest file correcting the assembly versions of MicrosoftSolverFoundationForExcel to
  6. Update the digital signatures for both the manifest and the VSTO file:
    mage.exe -update MicrosoftSolverFoundationForExcel.dll.manifest -CertFile <your-cert.pfx> -Password <cert-export-password>
    mage.exe -update MicrosoftSolverFoundationForExcel.vsto -appmanifest MicrosoftSolverFoundationForExcel.dll.manifest -CertFile <your-cert.pfx> -Password <cert-export-password>
  7. Restart Excel, the Solver Foundation tab should be on the ribbon

(Tested with Office 2010 beta.)

Rewriting Git History: Relocating Subversion URLs

Posted in .NET | Git at Thursday, June 25, 2009 8:59 PM W. Europe Daylight Time

Git LogoToday we changed the URL of our Subversion server at work to a new domain. Subversion and TortoiseSVN offer a separate relocate command for that, which basically updates the local working copy metadata.

Not so for Git. Git keeps SVN metadata in two places: the commit log messages themselves which hold a git-svn-id entry for all commits that have been pushed to SVN, and in the .git/config file.

commit e82751b4872142679ba61e26fc0c57e97c698e8f
Author: agross 
Date:   Thu Jun 25 16:44:55 2009 +0000

    Adding FxCop to the code quality task

    git-svn-id: https://your.svn-server/svn/Crimson/trunk@67 8ed4a44c-bfb4-4748-a28a-fad9255c4788
	repositoryformatversion = 0
	filemode = false
	bare = false
	logallrefupdates = true
	ignorecase = true
[svn-remote "svn"]
	url = https://your.svn-server/svn/Crimson/trunk
	fetch = :refs/remotes/git-svn

To update the SVN URL it’s required to update the Git configuration file (an easy edit) and also to rewrite the commit log messages, updating the values of git-svn-id to reflect the new SVN server URL. The latter can be achieved with the git-filter-branch command which allows you to dissect the project history in interesting ways.

Having several local Git repositories to update, I went for the scripted solution. I found this article on how to change the SVN repository URL and added some scripting goodness to it (aside from fixing the syntactic errors). It worked pretty good for my ~10 repositories.

  • You pass two arguments:
    • The old SVN URL, i.e. http://old.server
    • The new SVN URL, i.e. https://new.server
    • The old URL will be matched against git-svn-id entries with a regular expression, and the matched parts get replaced with the new URL.
  • Rewrite the commit log messages, thus updating git-svn-id
  • Create a backup copy of .git/config
  • Replace the old SVN URL in .git/config
  • Delete all metadata Git has aquired about SVN
  • Rebase against SVN, recreating the SVN metadata

# Must be called with two command-line args.
# Example: http://old.server https://new.server
if [ $# -ne 2 ]  
  echo "Please invoke this script with two command-line arguments (old and new SVN URLs)."
  exit $E_NO_ARGS

# Prepare URLs for regex search and replace.
oldUrl=`echo $1 | awk '{gsub("[\\\.]", "\\\\\\\&");print}'`
newUrl=`echo $2 | awk '{gsub("[\\\&]", "\\\\\\\&");print}'`

filter="sed \"s|^git-svn-id: $oldUrl|git-svn-id: $newUrl|g\""
git filter-branch --msg-filter "$filter" -- --all

sed -i.backup -e "s|$oldUrl|$newUrl|g" .git/config

rm -rf .git/svn
git svn rebase

Migrating SharePoint Content Databases To A New Farm While Keeping Security Settings

Posted in .NET | SharePoint | SQL Server at Saturday, April 25, 2009 4:40 PM W. Europe Daylight Time

The server this blog is hosted on was upgraded recently, i.e. is now run on a new dedicated server. Actually, next to this blog there’s a lot more going on. We, a bunch of geeks, are self-hosting mail, web sites, blogs and some collaboration tools like SharePoint (Windows SharePoint Services, in our case). Yeah, SharePoint, a true beast in and of itself. I can’t tell you how much I do not miss developing software for it and setting up customer sites.

I wanted to make the move to the new server as smooth as possible for our SharePoint users. Because we do not use Active Directory to authenticate our users, we obviously had to migrate the SharePoint user accounts manually. That is, re-create each user on the new server giving them a random password and communicate the change.

Moving a SharePoint site is surprisingly pretty well documented on TechNet, but won’t tell you about one important aspect: When you move the site to a new farm and the site does not use Active Directory, you will have to set up security anew.

Why? Because SharePoint matches user accounts by their SID, a value that is unique for each user account, even across machines: OLDMACHINE\foo’s SID is different from NEWMACHINE\foo’s SID. Burdening the four site collection administrator with this task is simply a no-go.

During my research how to work around that I found the Dustin Miller’s excellent post “Fix those SIDs”. It describes the process of massaging a SharePoint site collection database to replace old SIDs with the account SIDs of the current machine. I’ve extended it a bit, because I also decided to rename the SharePoint Search account while moving to the new server (note the extra REPLACE in line 11).

DECLARE @login nvarchar(255), @SystemId varbinary(512)

SELECT tp_Login, tp_SystemID FROM UserInfo WHERE tp_Deleted = 0

OPEN curUsers
FETCH NEXT FROM curUsers INTO @login, @systemid

    DECLARE @newLoginName AS nvarchar(255) = REPLACE(REPLACE(@login, 'OLDMACHINE', 'NEWMACHINE'), 'spsearch', 'sharepoint-search')
    DECLARE @newSID varbinary(85) = SUSER_SID(@newLoginName)
        PRINT 'Resetting user ' + @login + ' to new login ' + @newLoginName  + ' with SID '
        PRINT SUSER_SID(@newLoginName)

        UPDATE UserInfo
        SET    tp_SystemID = SUSER_SID(@newLoginName),
               tp_Login = @newLoginName
        WHERE CURRENT OF curUsers
    FETCH NEXT FROM curUsers INTO @login, @systemid

CLOSE curUsers

After the script ran, take a look at the UserInfo table and SELECT rows that still contain OLDMACHINE in the tp_Login column. This helps you get a quick overview of what accounts have been missed during account re-creation.

As an extra step, I found it appropriate to update the site’s user entry as well (the account name that shows up in the site’s user list when no full name is given) to reflect the new machine name.

UPDATE    [AllUserData]
SET       [nvarchar1] = REPLACE(REPLACE([nvarchar1], 'OLDMACHINE', 'NEWMACHINE'), 'spsearch', 'sharepoint-search'),
          [nvarchar2] = REPLACE(REPLACE([nvarchar2], 'OLDMACHINE', 'NEWMACHINE'), 'spsearch', 'sharepoint-search'),
          [nvarchar3] = REPLACE(REPLACE([nvarchar3], 'OLDMACHINE', 'NEWMACHINE'), 'spsearch', 'sharepoint-search')
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