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Recusively find a file in whole system, return first folder

I'm trying to make a recursive function to return the first folder where the file is found.
I don't use GetFiles because the function stop when there is an exception.
However, it always stops at the 2nd folder and don't return anything cause the file is not found. What am I doing wrong ?
private static bool IsDirFound = false;
private static string SearchFile(string directory)
{
var fileFound = Directory.GetFiles(directory).FirstOrDefault(f => f.EndsWith("file.exe"));
if (fileFound != null)
{
IsDirFound = true;
return directory;
}
else if (!IsDirFound)
{
foreach (string subDir in Directory.GetDirectories(directory))
{
try
{
Console.WriteLine(subDir);
return SearchFile(subDir); // it always stop a the 2nd folder
}
catch
{
// swallow
}
}
}
return null;
}

Be careful with recursive methods, its easy to cause a a stackoverflow exception
Here is your problem
else if (!IsDirFound) // When found
{
...
}
return null; // you return false
However i tweaked this to be a bit more powerful, obviously you'll get better performance without the Func however it is more usable.. I'll leave these details up to you.
Example
private static string SearchFile(string directory, Func<string, bool> condition)
{
// get all files
var files = Directory.GetFiles(directory);
// check the file against what you want
if (files.Any(condition.Invoke))
return directory; // if its found return
// get all dirs
var dirs = Directory.GetDirectories(directory);
// check each one
foreach (var dir in dirs)
{
Console.WriteLine($"Searching {dir}");
try
{
// recurse
var result = SearchFile(dir, condition);
// if its found return
if (result != null)
return result;
}
catch (Exception ex)
{
// log
Console.WriteLine(ex.Message);
}
}
// nothing found here bail
return null;
}
Usage
var result = SearchFile(#"D:\", file => file.EndsWith("test.blah") );

Not all Code Path returns a value

I have a method which is checking for write access of a folder. But its giving me error saying not all code path returns a value?
public bool AccessPackerPlanTemplate(string folderPath)
{
try
{
string path = #"\\Sample";
string NtAccountName = #"Sample";
DirectoryInfo di = new DirectoryInfo(path);
DirectorySecurity acl = di.GetAccessControl(AccessControlSections.All);
AuthorizationRuleCollection rules = acl.GetAccessRules(true, true, typeof(NTAccount));
//Go through the rules returned from the DirectorySecurity
foreach (AuthorizationRule rule in rules)
{
//If we find one that matches the identity we are looking for
if (rule.IdentityReference.Value.Equals(NtAccountName, StringComparison.CurrentCultureIgnoreCase))
{
//Cast to a FileSystemAccessRule to check for access rights
if ((((FileSystemAccessRule)rule).FileSystemRights & FileSystemRights.WriteData) > 0)
{
//Show the link
}
}
}
}
catch (UnauthorizedAccessException)
{
return false;
}
}
what am I missing in this method ?

If an error isn't thrown, no boolean gets returned.
You need a return true/false at the end, after the try/catch.
NOT throwing an error is a possible "code path" which the compiler needs a return type for.

You're only ever returning a value when an exception is caught. That's why your compiler is telling you that.

I'll recommend this for your method, because you're not returning a boolean on all ways:
public bool AccessPackerPlanTemplate(string folderPath)
{
bool result = false;
try
{
string path = #"\\Sample";
string NtAccountName = #"Sample";
//... Your code
if(/*Your Condition*/)
{
result = true;
}
}
catch (UnauthorizedAccessException)
{
result = false;
}
return result;
}

Easiest way in C# to find out if an app is running from a network drive?

I want to programmatically find out if my application is running from a network drive. What is the simplest way of doing that? It should support both UNC paths (\\127.0.0.1\d$) and mapped network drives (Z:).

This is for mapped drive case. You can use the DriveInfo class to find out whether drive a is a network drive or not.
DriveInfo info = new DriveInfo("Z");
if (info.DriveType == DriveType.Network)
{
// Running from network
}
Complete method and Sample Code.
public static bool IsRunningFromNetwork(string rootPath)
{
try
{
System.IO.DriveInfo info = new DriveInfo(rootPath);
if (info.DriveType == DriveType.Network)
{
return true;
}
return false;
}
catch
{
try
{
Uri uri = new Uri(rootPath);
return uri.IsUnc;
}
catch
{
return false;
}
}
}
static void Main(string[] args)
{
Console.WriteLine(IsRunningFromNetwork(System.IO.Path.GetPathRoot(AppDomain.CurrentDomain.BaseDirectory))); }

if (new DriveInfo(Application.StartupPath).DriveType == DriveType.Network)
{
// here
}

This is my current method of doing this, but it feels like there should be a better way.
private bool IsRunningFromNetworkDrive()
{
var dir = AppDomain.CurrentDomain.BaseDirectory;
var driveLetter = dir.First();
if (!Char.IsLetter(driveLetter))
return true;
if (new DriveInfo(driveLetter.ToString()).DriveType == DriveType.Network)
return true;
return false;
}

In case using UNC path it is quitely simple - examine host name in UNC and test that it is localhost(127.0.0.1, ::1, hostname, hostname.domain.local, ip-addresses of workstation) or not.
If the path is not UNC - extract the drive letter from path and test the DriveInfo class for its type

I rearranged the solution of dotnetstep, which is in my opinion better because it avoids exceptions when a valid path is passed, and it throws an exception if there is a wrong path passed, which does not allow to make an assumption of true or false.
//----------------------------------------------------------------------------------------------------
/// <summary>Gets a boolean indicating whether the specified path is a local path or a network path.</summary>
/// <param name="path">Path to check</param>
/// <returns>Returns a boolean indicating whether the specified path is a local path or a network path.</returns>
public static Boolean IsNetworkPath(String path) {
Uri uri = new Uri(path);
if (uri.IsUnc) {
return true;
}
DriveInfo info = new DriveInfo(path);
if (info.DriveType == DriveType.Network) {
return true;
}
return false;
}
Test:
//----------------------------------------------------------------------------------------------------
/// <summary>A test for IsNetworkPath</summary>
[TestMethod()]
public void IsNetworkPathTest() {
String s1 = #"\\Test"; // unc
String s2 = #"C:\Program Files"; // local
String s3 = #"S:\"; // mapped
String s4 = "ljöasdf"; // invalid
Assert.IsTrue(RPath.IsNetworkPath(s1));
Assert.IsFalse(RPath.IsNetworkPath(s2));
Assert.IsTrue(RPath.IsNetworkPath(s3));
try {
RPath.IsNetworkPath(s4);
Assert.Fail();
}
catch {}
}

DriveInfo m = DriveInfo.GetDrives().Where(p => p.DriveType == DriveType.Network).FirstOrDefault();
if (m != null)
{
//do stuff
}
else
{
//do stuff
}

GetAccessControl error with NTAccount

private bool HasRights(FileSystemRights fileSystemRights_, string fileName_, bool isFile_)
{
bool hasRights = false;
WindowsIdentity WinIdentity = System.Security.Principal.WindowsIdentity.GetCurrent();
WindowsPrincipal WinPrincipal = new WindowsPrincipal(WinIdentity);
AuthorizationRuleCollection arc = null;
if (isFile_)
{
FileInfo fi = new FileInfo(#fileName_);
arc = fi.GetAccessControl().GetAccessRules(true, true, typeof(NTAccount));
}
else
{
DirectoryInfo di = new DirectoryInfo(#fileName_);
arc = di.GetAccessControl().GetAccessRules(true, true, typeof(NTAccount));
}
foreach (FileSystemAccessRule rule in arc)
{
if (WinPrincipal.IsInRole(rule.IdentityReference.Value))
{
if (((int)rule.FileSystemRights & (int)fileSystemRights_) > 0)
{
if (rule.AccessControlType == AccessControlType.Allow)
hasRights = true;
else if (rule.AccessControlType == AccessControlType.Deny)
{
hasRights = false;
break;
}
}
}
}
return hasRights;
}
The above code block is causing me problems. When the WinPrincipal.IsInRole(rule.IdentityReference.Value) is executed the following exception occurs:
"The trust relationship between the primary domain and the trusted domain failed.".
I'm very new to using identities, principles and such so I don't know what's the problem. I'm assuming it's with the use of NTAccount?
Thanks

I could try to address your question by suggesting you use a SecurityIdentifier, but there are many other issues here that would still be show-stoppers even if this were addressed. I'm not talking about inefficiencies such as using FileInfo instead of File, but the basic logic you're trying to use to interpret the DACL.
Take a look at: http://msdn.microsoft.com/en-us/library/cc230290(PROT.10).aspx

Checking for directory and file write permissions in .NET

In my .NET 2.0 application, I need to check if sufficient permissions exist to create and write to files to a directory. To this end, I have the following function that attempts to create a file and write a single byte to it, deleting itself afterwards to test that permissions do exist.
I figured the best way to check was to actually try and do it, catching any exceptions that occur. I'm not particularly happy about the general Exception catch though, so is there a better or perhaps a more accepted way of doing this?
private const string TEMP_FILE = "\\tempFile.tmp";
/// <summary>
/// Checks the ability to create and write to a file in the supplied directory.
/// </summary>
/// <param name="directory">String representing the directory path to check.</param>
/// <returns>True if successful; otherwise false.</returns>
private static bool CheckDirectoryAccess(string directory)
{
bool success = false;
string fullPath = directory + TEMP_FILE;
if (Directory.Exists(directory))
{
try
{
using (FileStream fs = new FileStream(fullPath, FileMode.CreateNew,
FileAccess.Write))
{
fs.WriteByte(0xff);
}
if (File.Exists(fullPath))
{
File.Delete(fullPath);
success = true;
}
}
catch (Exception)
{
success = false;
}
}

Directory.GetAccessControl(path) does what you are asking for.
public static bool HasWritePermissionOnDir(string path)
{
var writeAllow = false;
var writeDeny = false;
var accessControlList = Directory.GetAccessControl(path);
if (accessControlList == null)
return false;
var accessRules = accessControlList.GetAccessRules(true, true,
typeof(System.Security.Principal.SecurityIdentifier));
if (accessRules ==null)
return false;
foreach (FileSystemAccessRule rule in accessRules)
{
if ((FileSystemRights.Write & rule.FileSystemRights) != FileSystemRights.Write)
continue;
if (rule.AccessControlType == AccessControlType.Allow)
writeAllow = true;
else if (rule.AccessControlType == AccessControlType.Deny)
writeDeny = true;
}
return writeAllow && !writeDeny;
}
(FileSystemRights.Write & rights) == FileSystemRights.Write is using something called "Flags" btw which if you don't know what it is you should really read up on :)

Deny takes precedence over Allow. Local rules take precedence over inherited rules. I have seen many solutions (including some answers shown here), but none of them takes into account whether rules are inherited or not. Therefore I suggest the following approach that considers rule inheritance (neatly wrapped into a class):
public class CurrentUserSecurity
{
WindowsIdentity _currentUser;
WindowsPrincipal _currentPrincipal;
public CurrentUserSecurity()
{
_currentUser = WindowsIdentity.GetCurrent();
_currentPrincipal = new WindowsPrincipal(_currentUser);
}
public bool HasAccess(DirectoryInfo directory, FileSystemRights right)
{
// Get the collection of authorization rules that apply to the directory.
AuthorizationRuleCollection acl = directory.GetAccessControl()
.GetAccessRules(true, true, typeof(SecurityIdentifier));
return HasFileOrDirectoryAccess(right, acl);
}
public bool HasAccess(FileInfo file, FileSystemRights right)
{
// Get the collection of authorization rules that apply to the file.
AuthorizationRuleCollection acl = file.GetAccessControl()
.GetAccessRules(true, true, typeof(SecurityIdentifier));
return HasFileOrDirectoryAccess(right, acl);
}
private bool HasFileOrDirectoryAccess(FileSystemRights right,
AuthorizationRuleCollection acl)
{
bool allow = false;
bool inheritedAllow = false;
bool inheritedDeny = false;
for (int i = 0; i < acl.Count; i++) {
var currentRule = (FileSystemAccessRule)acl[i];
// If the current rule applies to the current user.
if (_currentUser.User.Equals(currentRule.IdentityReference) ||
_currentPrincipal.IsInRole(
(SecurityIdentifier)currentRule.IdentityReference)) {
if (currentRule.AccessControlType.Equals(AccessControlType.Deny)) {
if ((currentRule.FileSystemRights & right) == right) {
if (currentRule.IsInherited) {
inheritedDeny = true;
} else { // Non inherited "deny" takes overall precedence.
return false;
}
}
} else if (currentRule.AccessControlType
.Equals(AccessControlType.Allow)) {
if ((currentRule.FileSystemRights & right) == right) {
if (currentRule.IsInherited) {
inheritedAllow = true;
} else {
allow = true;
}
}
}
}
}
if (allow) { // Non inherited "allow" takes precedence over inherited rules.
return true;
}
return inheritedAllow && !inheritedDeny;
}
}
However, I made the experience that this does not always work on remote computers as you will not always have the right to query the file access rights there. The solution in that case is to try; possibly even by just trying to create a temporary file, if you need to know the access right before working with the "real" files.

The answers by Richard and Jason are sort of in the right direction. However what you should be doing is computing the effective permissions for the user identity running your code. None of the examples above correctly account for group membership for example.
I'm pretty sure Keith Brown had some code to do this in his wiki version (offline at this time) of The .NET Developers Guide to Windows Security. This is also discussed in reasonable detail in his Programming Windows Security book.
Computing effective permissions is not for the faint hearted and your code to attempt creating a file and catching the security exception thrown is probably the path of least resistance.

The accepted answer by Kev to this question doesn't actually give any code, it just points to other resources that I don't have access to. So here's my best attempt at the function. It actually checks that the permission it's looking at is a "Write" permission and that the current user belongs to the appropriate group.
It might not be complete with regard to network paths or whatever, but it's good enough for my purpose, checking local configuration files under "Program Files" for writability:
using System.Security.Principal;
using System.Security.AccessControl;
private static bool HasWritePermission(string FilePath)
{
try
{
FileSystemSecurity security;
if (File.Exists(FilePath))
{
security = File.GetAccessControl(FilePath);
}
else
{
security = Directory.GetAccessControl(Path.GetDirectoryName(FilePath));
}
var rules = security.GetAccessRules(true, true, typeof(NTAccount));
var currentuser = new WindowsPrincipal(WindowsIdentity.GetCurrent());
bool result = false;
foreach (FileSystemAccessRule rule in rules)
{
if (0 == (rule.FileSystemRights &
(FileSystemRights.WriteData | FileSystemRights.Write)))
{
continue;
}
if (rule.IdentityReference.Value.StartsWith("S-1-"))
{
var sid = new SecurityIdentifier(rule.IdentityReference.Value);
if (!currentuser.IsInRole(sid))
{
continue;
}
}
else
{
if (!currentuser.IsInRole(rule.IdentityReference.Value))
{
continue;
}
}
if (rule.AccessControlType == AccessControlType.Deny)
return false;
if (rule.AccessControlType == AccessControlType.Allow)
result = true;
}
return result;
}
catch
{
return false;
}
}

IMO, you need to work with such directories as usual, but instead of checking permissions before use, provide the correct way to handle UnauthorizedAccessException and react accordingly. This method is easier and much less error prone.

Try working with this C# snippet I just crafted:
using System;
using System.IO;
using System.Security.AccessControl;
using System.Security.Principal;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string directory = #"C:\downloads";
DirectoryInfo di = new DirectoryInfo(directory);
DirectorySecurity ds = di.GetAccessControl();
foreach (AccessRule rule in ds.GetAccessRules(true, true, typeof(NTAccount)))
{
Console.WriteLine("Identity = {0}; Access = {1}",
rule.IdentityReference.Value, rule.AccessControlType);
}
}
}
}
And here's a reference you could also look at. My code might give you an idea as to how you could check for permissions before attempting to write to a directory.

according to this link:
http://www.authorcode.com/how-to-check-file-permission-to-write-in-c/
it's easier to use existing class SecurityManager
string FileLocation = #"C:\test.txt";
FileIOPermission writePermission = new FileIOPermission(FileIOPermissionAccess.Write, FileLocation);
if (SecurityManager.IsGranted(writePermission))
{
// you have permission
}
else
{
// permission is required!
}
but it seems it's been obsoleted, it is suggested to use PermissionSet instead.
[Obsolete("IsGranted is obsolete and will be removed in a future release of the .NET Framework. Please use the PermissionSet property of either AppDomain or Assembly instead.")]

Since the static method 'GetAccessControl' seems to be missing from the present version of .Net core/Standard I had to modify #Bryce Wagner's answer (I went ahead and used more modern syntax):
public static class PermissionHelper
{
public static bool? CurrentUserHasWritePermission(string filePath)
=> new WindowsPrincipal(WindowsIdentity.GetCurrent())
.SelectWritePermissions(filePath)
.FirstOrDefault();
private static IEnumerable<bool?> SelectWritePermissions(this WindowsPrincipal user, string filePath)
=> from rule in filePath
.GetFileSystemSecurity()
.GetAccessRules(true, true, typeof(NTAccount))
.Cast<FileSystemAccessRule>()
let right = user.HasRightSafe(rule)
where right.HasValue
// Deny takes precedence over allow
orderby right.Value == false descending
select right;
private static bool? HasRightSafe(this WindowsPrincipal user, FileSystemAccessRule rule)
{
try
{
return user.HasRight(rule);
}
catch
{
return null;
}
}
private static bool? HasRight(this WindowsPrincipal user,FileSystemAccessRule rule )
=> rule switch
{
{ FileSystemRights: FileSystemRights fileSystemRights } when (fileSystemRights &
(FileSystemRights.WriteData | FileSystemRights.Write)) == 0 => null,
{ IdentityReference: { Value: string value } } when value.StartsWith("S-1-") &&
!user.IsInRole(new SecurityIdentifier(rule.IdentityReference.Value)) => null,
{ IdentityReference: { Value: string value } } when value.StartsWith("S-1-") == false &&
!user.IsInRole(rule.IdentityReference.Value) => null,
{ AccessControlType: AccessControlType.Deny } => false,
{ AccessControlType: AccessControlType.Allow } => true,
_ => null
};
private static FileSystemSecurity GetFileSystemSecurity(this string filePath)
=> new FileInfo(filePath) switch
{
{ Exists: true } fileInfo => fileInfo.GetAccessControl(),
{ Exists: false } fileInfo => (FileSystemSecurity)fileInfo.Directory.GetAccessControl(),
_ => throw new Exception($"Check the file path, {filePath}: something's wrong with it.")
};
}

private static void GrantAccess(string file)
{
bool exists = System.IO.Directory.Exists(file);
if (!exists)
{
DirectoryInfo di = System.IO.Directory.CreateDirectory(file);
Console.WriteLine("The Folder is created Sucessfully");
}
else
{
Console.WriteLine("The Folder already exists");
}
DirectoryInfo dInfo = new DirectoryInfo(file);
DirectorySecurity dSecurity = dInfo.GetAccessControl();
dSecurity.AddAccessRule(new FileSystemAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), FileSystemRights.FullControl, InheritanceFlags.ObjectInherit | InheritanceFlags.ContainerInherit, PropagationFlags.NoPropagateInherit, AccessControlType.Allow));
dInfo.SetAccessControl(dSecurity);
}