We Keep Coding

Changing the current working directory of cmd (from a child process)

So I am trying to write a cd -like program that can be executed using cmd and after it exits the working directory of the calling cmd process should be changed.
Now before this post is flagged as a duplicate: I am aware of this and this question that were asked for pretty much this exact problem but using Linux instead of Windows as well as being pretty broad and unspecific, and I am aware that similar limitations apply to Windows as well (changing the working directory of my process will not change the parent’s working directory).
There is actually is a working solution to this for linux. However it is using gdb for this, and I would like to achieve this task using only built-in Windows utilities (WinAPI, dotNET, etc.).
What I have tried so far
I did manage to use Cheat Engine and the OpenProcess() / WriteProcessMemory() WinAPI funtions to successfully override cmd's working directory. However this solution feels sloppy and doesn't work well (or at least requires more work to be put into.)
My question
Is there a different (maybe simpler?) way on Windows to achieve this? Like a way to invoke/inject code to the cmd process to execute cd whatever\directory\I\want directly without overriding its memory? I have seen the CreateRemoteThread() functions however I didn't manage to find a way to put them to use.
FYI: I am mainly using C# but C/C++ solutions should help too as long as they are based on the native Microsoft libraries.

This post describes a Windows implementation of a function that launches a child process, creates pipes to stdin and stdout from which a command is sent, and a response is returned. Finally, once all response is captured the child process is terminated. If this sounds familiar it is similar in concept to Linux's popen() function with the exception that this implementation was specifically created to capture the response into a buffer of any command that returns one. (Also included is a variant for use when no-response is expected or needed.)
The full source can be adapted for use within a standalone executable, or as an API. (.dll) Either way, the resulting functions accept and process any command using standard Windows CMD syntax. The function cmd_rsp(...) returns the Windows response via stdout into a self-sizing buffer.
The exported prototypes are:
int __declspec(dllexport) cmd_rsp(const char *command, char **chunk, unsigned int size);
int __declspec(dllexport) cmd_no_rsp(const char *command);
A simple use case when capturing a response:
#include "cmd_rsp.h"
int main(void)
{
char *buf = {0};
buf = calloc(100, 1);//initialize to some initial size
if(!buf)return 0;
cmd_rsp("dir /s", &buf, 100);//buffer will grow to accommodate response as needed.
printf("%s", buf);
free(buf);
return 0;
}
A simple use case when response is not needed:
#include "cmd_rsp.h"
int main(void)
{
cmd_no_rsp("cd C:\\dir1\\dir2");
return 0;
}
A detailed description of purpose and usage is described in the link provided above. To illustrate, here are a few sample command inputs, each in this case change the working directory, then execute a command from that directory:
A command to change to sqlite directory, then execute a query:
cd c:\\tempExtract\\sqlite\\Tools\\sqlite-tools-win32-x86-3250300 && sqlite3.exe .\\extract.db \"select * from event, eventdata where eventType=38 and eventdata .eventid=event.eventid\
A command to change to teraterm directory, then execute a script:
"c:\\Program Files (x86)\\teraterm\" && ttpmacro c:\\DevPhys\\LPCR_2\\play\\Play.ttl
A command to change directory then execute a command to send multiple digital acquisition channel settings.
cd C:\\Dir1\\Dir2\\Dir3\\support\\Exes\\WriteDigChannel && .\\WriteDigChannel.exe P1_CH0 1 && .\\WriteDigChannel.exe P1_C H0 0 && .\\WriteDigChannel.exe P1_CH0 1
A recursive directory search from a specified location:
cd C:\\dir1\\dir2 && dir /s /b

I got it working. As was suggested SendInput finally did the trick.
I used a combination of WinAPI calls to GetForegroundWindow() / SetForegroundWindow() and the Windows Forms System.Windows.Forms.SendKeys.SendWait() Method to achieve what I wanted:
Upon calling my cd-wrapper program (sd.exe) and providing my custom target directory (~/ home) it generates the corresponding command along with the "Enter-Pressed-Event" to be sent to it's parent cmd process.
Here's the complete C# code:
if (args.Length != 1)
{
Console.WriteLine(Directory.GetCurrentDirectory());
return;
}
string targetDirectory = args[0];
string command = string.Empty;
if (targetDirectory.Equals("~"))
{
command = #"pushd C:\Users\fred\Desktop";
}
else if (!Directory.Exists(targetDirectory))
{
Console.WriteLine("I/O Error: No such file or directory.");
return;
}
else
{
command = #"cd " + targetDirectory;
}
Target target = Target.Create(Process.GetCurrentProcess().GetParentProcess());
target.SendKeys(command + "{ENTER}", true);
Note that I kind of started to write a complete Framework for this and similar problems alongside this project that contains all my different approaches to this question and the low level WinAPI calls as well as the Extension methods to get the parent process :D
As it would be a bit overkill to paste all of it's code in this answer, here's the GitHub. If I can find the time I'll go ahead and optimize the code, but for now this'll do. Hope this helps anyone encountering a similar problem :)
Edit:
An even "cleaner" way is to use dll injection to directly make cmd switch it's working directory. While it is a lot harder to get working it has the advantage of not littering the cmd command history as compared to the approach described above. In addition to that cmd seems to be aware of any changes to it's current working directory, so it automatically updates the prompt text. Once I have a fully working example, that allows to dynamically specify the target directory I will post it here :)

Roslyn Scripting - Script without "System"

As of this article I want to write a little C# scripting engine to work. I have tried this code:
System.IO.StreamReader sr = new System.IO.StreamReader("example.txt");
var prog = sr.ReadToEnd();
sr.Close();
ScriptOptions so = ScriptOptions.Default;
Console.WriteLine(CSharpScript.RunAsync(prog, so).Result.GetVariable("sum").Value);
Console.ReadKey();
And the file content of example.txt is:
System.IO.StreamReader sr = new System.IO.StreamReader("foo.txt");
string s = sr.ReadToEnd();
int sum = System.Convert.ToInt32(s);
Now I want to restrict the user to only basic functions of C# (using int, string, while, for) and some self defined functions but NOT the whole .NET library. But even if I don't include System.IO als reference the user can type System.IO.something and will get the right thing.
Is there a possibility to remove the access to "System" from the script?
I'm glad with any answer.

You'll need to set up the ScriptingOptions properly, meaning that a custom MetadataReferenceResolver needs to be used instead of the default one, which is resolving the missing references automatically. I don't know if there is already a resolver that only resolves assemblies based on its parameters, but you can certainly implement yours. Check out the TestMetadataReferenceResolver, which does something similar.
Update
This won't work for things that are defined in mscorlib.

How can I get another application's installation path programmatically?

I'd like to know where the installation path for an application is. I know it usually is in ...\Program Files... but I guess some people install it in different locations. I do know the name of the application.
Thank you.

The ideal way to find a program's installation path (on Windows) is to read it from the registry. Most installers will create a registry key for that program that contains the installation path. Exactly where this key is and what it will be named varies depending on the program in question.
To find if the program has a key in the registry, open 'regedit' and use the Edit > Find option to try and locate a key with the program name. If such a key exists, you can read it using the RegistryKey class in the .NET Framework library.
If the program does not have a registry key then another option is just to ask the user to locate the .exe file with the OpenFileDialog, although this is obviously not ideal.

Many (most?) programs create an App Paths registry key. Have a look at
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths

If you know the application in question (as compared to any application) registry key is the probably the best option (if one exists).
The install might put in its own custom "install path key" somewhere (so do a find as Fara mentioned) or it might be in the uninstall section for installed programs, so you could check:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
But be aware that any new version of an install could change the key it writes out, both for a custom key or for the uninstall entry. So checking the registry should probably be only for a known install\version.
tep

Best way is to use Installer APIs to find the program location.
You can write a Managed wrapper over the APIs
Search for MsiGetProductInfo
Reference: http://msdn.microsoft.com/en-us/library/aa369558(VS.85).aspx

You can use MSI (I wrote a C# wrapper for it here https://github.com/alialavia/MSINet). Here is a simple example:
var location = "";
foreach (var p in InstalledProduct.Enumerate())
{
try
{
if (p.InstalledProductName.Contains("AppName"))
{
location = p.InstallLocation;
break;
}
}
catch { }
}

Take a look in the registry.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\
or
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\
Each of the above contain a list of sub-keys, one for each installed application (as it appears, for example, in the "Programs and Features" applet)
You can search for your application there, or if you know the product code, access it directly.
public string GetInstallPath(string applicationName)
{
var installPath = FindApplicationPath(#"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", applicationName);
if (installPath == null)
{
installPath = FindApplicationPath(#"SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall", applicationName);
}
return installPath;
}
private string FindApplicationPath(string keyPath, string applicationName)
{
var hklm = Registry.LocalMachine;
var uninstall = hklm.OpenSubKey(keyPath);
foreach (var productSubKey in uninstall.GetSubKeyNames())
{
var product = uninstall.OpenSubKey(productSubKey);
var displayName = product.GetValue("DisplayName");
if (displayName != null && displayName.ToString() == applicationName)
{
return product.GetValue("InstallLocation").ToString();
}
}
return null;
}

Issues about files or folders in use: get the name of another Process that use file or folder

I using C# .NET , vs 2008 , .net 3.5
For me, is difficult, but I need sample code in C# for this:
Check if a file or a folder is in use
If file or a folder is in use, the name of Process that use it
For example, in my issue.
I try delete file, and I get "The process cannot access the file 'XYZ' because it is being used by another process." Exception.
File.Delete(infoFichero.Ruta);
I want check if a file is in use, and the name of Process that use it.
I need sample code, source code, please. I dont want use c++, I dont know c, c++, unmanaged code, or WinApi. I want use only C# code (managed code .net).
I have read several references but not get sample code source,
How to check if a file is in use?
Emulate waiting on File.Open in C# when file is locked
http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/9dabc172-237a-42db-850e-ada08885a5d5
How to check if a file is in use?
Easiest way to read text file which is locked by another application
Using C# is it possible to test if a lock is held on a file
EDIT:
From Yan Jun - MSFT
string path = "D:\\temp2.xlsx";
foreach (Process c in Process.GetProcesses()) {
if (c.MainWindowTitle.Contains(Path.GetFileName(path))){
MessageBox.Show(c.ProcessName);
return;
}
}
try{
FileInfo f = new FileInfo(path);
f.Delete();
}
catch (Exception ex){
MessageBox.Show(ex.Message);
}
...
But it is difficult get solution for all 100% issues.
Problem if c.MainWindowTitle == null or not contains filename.
Problem for shared folder in another machine, PC, server,... like:
File.Delete(#\desiis\TEmporal\Project\script.targets);
any sample code, I ask for help gurus, MVPs, anyone.
UPDATE: the same issue for a folder

There's not going to be a way to find the process that has the file opened without stepping into the WinApi, I don't think. And as far as checking whether its in use, the only thing you can really do, as the SO questions you linked to state, is to wrap the file access attempts in a try/catch block.
The code to find which file has it opened is likely to be ugly, but there may be an API out there that wraps this up nicely. There are 3rd party utilities that will tell you this (Unlocker being the best known example). You can also use ProcessExplorer to search for open file handles by the filename. Those don't really help you though.
The short answer of what I'm trying to get across here is you have the answer for the first part of your question in the SO questions you already linked, and the second part would probably require WIN32 calls, which you want to avoid, but you're probably going to have to get your hands dirty in Win32... Still want help?
EDIT: You could shell out to sysinternals Handle utility. You would need to get the output of that command and parse it yourself. You can read the executed process's output like this
string result = proc.StandardOutput.ReadToEnd();
The issue with this is you're going to get a license agreement popup the first time you run the Handle utility. Not to mention the whole licensing issues if this is something you hope to deploy...
If you're still interested, I can show you how you'd go about this.
EDIT: Here's a runnable program that will find the exe name and pid of any program that has an open handle to a file. I added comments, but can elaborate further if necessary. I use Regular Expressions here to parse the output as that makes the most sense given the task at hand.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Text.RegularExpressions;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
ProcessStartInfo si = new ProcessStartInfo();
si.FileName = "handle.exe"; //name of the handle program from sysinternals
//assumes that its in the exe directory or in your path
//environment variable
//the following three lines are required to be able to read the output (StandardOutput)
//and hide the exe window.
si.RedirectStandardOutput = true;
si.WindowStyle = ProcessWindowStyle.Hidden;
si.UseShellExecute = false;
si.Arguments = "test.xlsx"; //this is the file you're trying to access that is locked
//these 4 lines create a process object, start it, then read the output to
//a new string variable "s"
Process p = new Process();
p.StartInfo = si;
p.Start();
string s = p.StandardOutput.ReadToEnd();
//this will use regular expressions to search the output for process name
//and print it out to the console window
string regex = #"^\w*\.EXE";
MatchCollection matches = Regex.Matches(s, regex, RegexOptions.Multiline);
foreach (var match in matches)
{
Console.WriteLine(match);
}
//this will use regex to search the output for the process id (pid)
//and print it to the console window.
regex = #"pid: (?<pid>[0-9]*)";
matches = Regex.Matches(s, regex, RegexOptions.Multiline);
foreach (var obj in matches)
{
Match match = (Match)obj; //i have to cast to a Match object
//to be able to get the named group out
Console.WriteLine(match.Groups["pid"].Value.ToString());
}
Console.Read();
}
}
}

There is no purely managed way to do this. You have to use some low-level APIs through P/invoke or similar.
There's good information here on a way to do it, but it's C++ code. You'd have to do the porting yourself.
http://www.codeproject.com/KB/shell/OpenedFileFinder.aspx
Note there are some complex issues with this, namely the issues around kernel vs. userspace memory. This is not a simple problem you're trying to solve.

Try the windows Process Explorer:
http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx
Won't let you do it from code, but at least you can figure out what the source of your locks are.

Is there a way to follow a windows fileystem shortcuts programatically in C# without using COM?

Back in .NET 1.0 days I wrote a method to return the target of a shortcut on MS Windows. It did this through using an interop to the Windows Script Hosting Object Model and brute forced through the COM interface:
private FileInfo GetFileFromShortcut(FileInfo shortcut)
{
FileInfo targetFile = null;
try
{
IWshRuntimeLibrary.WshShell wShell = new IWshRuntimeLibrary.WshShellClass();
IWshRuntimeLibrary.WshShortcut wShortcut = (IWshRuntimeLibrary.WshShortcut)wShell.CreateShortcut(shortcut.FullName);
// if the file wasn't a shortcut then the TargetPath comes back empty
string targetName = wShortcut.TargetPath;
if (targetName.Length > 0)
{
targetFile = new FileInfo(targetName);
}
}
catch (Exception)
{ // will return a null targetFile if anything goes wrong
}
return targetFile;
}
This still bugs me, and I was looking to replace this with something more elegant, but only if the replacement actually works at least as well. I still can't find a native C# way of finding the target of a shortcut. Is there one, or is this still the best way of doing this type of thing?

It looks like someone has written a class to manipulate shortcut files in C# called ShellLink, but it too uses COM.

Can't you just open the .lnk or .url file and parse it?
This talks about the same thing and shows what the files look like:
http://www.programmingtalk.com/showthread.php?t=7335

I got interested in this as well a while ago.
Here is the accepted response with a link to a (informal) description of the format of LNK files. Apparently, all available methods yet go through some API.