Wolfgang Riedmann Blog

These days, I was working on a webservice that worked directly with http.sys.
This service was planned to wait for requests, and launch programs depending on the request.
Firstly, I planned to use the local system account, and launch the external programs as specific user. This program should be started from a network share, using UNC paths.
Unfortunately, that does not work, Process.Start cannot do that:
http://blogs.msdn.com/b/winsdk/archive/2013/11/12/runas-verb-process-start-doesn-t-work-from-a-localsystem-net-service.aspx

My next decision was to add a user for this purpose (to run the Windows service). Unfortunately, Process.Start ignores the essential settings for a Windows service

oInfo:UseShellExecute := false
oInfo:CreateNoWindow := true
oInfo:ErrorDialog := false
oInfo:WindowStyle := ProcessWindowStyle.Hidden

The page from MSDN (https://msdn.microsoft.com/library/0w4h05yb%28v=vs.100%29.aspx) states:
“If the UserName and Password properties of the StartInfo instance are set, the unmanaged CreateProcessWithLogonW function is called, which starts the process in a new window even if the CreateNoWindow property value is true or the WindowStyle property value is Hidden.”
At the moment I’m not changing the user from the service, but executing the external program under the service account.

I had also another small issue: since I was reading the password from an ini file, I thought the StartInfo:PasswordInClearText property was enough. On my development machine it worked, but crashed on the production server, an SBS 2011 (based on Windows Server 2008 R2) because with the .NET Framework 4 this property simply does not exists.

Another issue: if you plan to start a process as another user from a service: this user needs local logon rights (on a server OS this is a manual change)

In some of my software programs, I have integrated a thing like document archiving, and there customers are putting several files, mostly PDF.

Since Adobe Reader is out and installed on the machines, often PDF files that are on a shared network folder, cannot be opened anymore – Adobe Reader gives an “access denied” error.

It is the “Protected Mode” of Adobe Reader that gives this problem.

Fortunately you can disable this mode, and Adobe Reader works again as expected. Please don’t forget to enable the protected mode afterwards!

This is my VO code for this functionality:

// disable Adobe Reader protected mode
aVersions := { “11.0”, “DC” }
aReset := {}
nLen := ALen( aVersions )
for nI := 1 upto nLen
 cVersion := aVersions[nI]
 nMode := RegistryDWord( HKEY_CURRENT_USER, “Software\Adobe\Acrobat Reader\” + cVersion + “\Privileged”, “bProtectedMode” )
 if nMode == 1
  SetRegistryDWord( HKEY_CURRENT_USER, “Software\Adobe\Acrobat Reader\” + cVersion + “\Privileged”, “bProtectedMode”, 0 )
  AAdd( aReset, cVersion )
 endif
next
oProcess := SpawnProcess{ cExe, cFileName, SW_NORMAL }
for nI := 1 upto 20
 ApplicationExec( EXECWHILEEVENT )
 Sleep( 500 ) // let Acrobat reader start
next
// re-enable Adobe Reader protected mode
nLen := ALen( aReset )
for nI := 1 upto nLen
 cVersion := aReset[nI]
 nMode := RegistryDWord( HKEY_CURRENT_USER, “Software\Adobe\Acrobat Reader\” + cVersion + “\Privileged”, “bProtectedMode” )
 if nMode == 0
  SetRegistryDWord( HKEY_CURRENT_USER, “Software\Adobe\Acrobat Reader\” + cVersion + “\Privileged”, “bProtectedMode”, 1 )
  AAdd( aReset, cVersion )
 endif
next

Today unfortunately I have discovered that WinINet calls don’t work in a service.

I need to put a file with FTP somewhere and call than a URL with http to update the data.

Microsoft says that instead of WinINet in a service the WinHTTP functions should be used. Unfortunately, WinHTTP has no support for FTP, so you need to use a 3rd party library in a Win32 service. (I used FCE from Marshallsoft).
And then: the WinHTTP interface is much more complicated to call than WinINET, and after working for a while on the WinHTTP interface (unfortunately it is not implemented in Visual Objects) I decided to use an external call to cURL.

Today, I had the need to intercept the paste of text in a RTF control to remove some formattings (font type and size).

Unfortunately the Richtext control is a special beast, and this is not possible before Windows 8.

On Windows 8, EN_CLIPFORMAT message is sent to the owner window, but unfortunately at this moment there is no way to do this on versions before (I need Windows 7 support). More informations you can find on stackoverflow.com:

http://stackoverflow.com/questions/5618162/detecting-if-paste-event-occurred-inside-a-rich-text-box

My (not perfect) solution consists in a extra context menu on the control that calls my own Paste method.

Since I had added SSL support to the SMTP sending from my application using stunnel, some users don’t opened up the firewall when requested from the operating system (from Windows Vista up).

Therefore I needed to open up the firewall directly from the application.

Since I don’t like to have run the application with elevated rights, I decided to make this change from an external app to spawn from my own application.

It is very simply to add a firewall rule using the netsh command:

netsh advfirewall firewall add rule name=”stunnel” dir=in action=allow program=”c:\tools\stunnel.exe” enable=yes profile=any

(where the stunnel.exe path should be adapted to your own settings).

The problem now was that this command needed to be run with elevated rights, and there is no option to do so.
After a quick search on the internet, I found elevate.exe – a small .NET executable that does what I need: launch a program with elevated rights.

So it was easy: launch elevate.exe (downloadable with sources) and pass as command line the call to netsh.exe.

Recently I had several cases of missing records on a customers network: sometimes added records were missing, indices were corrupted or records incomplete.

Since this occurred with an application that on all other customers worked very well for years without any problems, I have researched until I found this link:

http://www.alaska-software.com/fixes/smb2/overview.shtm

This MSI adds three entries at

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanWorkstation\Parameters

In my application I have added the following code:

This solved the problem.