Windows User: SID and name

I wasted much time trying to find easy way how in C# .NET get SID by user name and back, w/o writing C++ dll. I already spend two days once for such dll, but I lost it or something. However, I spent two hours in google groups and web search, untill I found so nice article.

Sections import Win32 functions to C#, and two functions.

Import section

private static extern bool LookupAccountSid( [In,MarshalAs(UnmanagedType.LPTStr)] string systemName, IntPtr sid, [Out,MarshalAs(UnmanagedType.LPTStr)] StringBuilder name, ref int cbName, StringBuilder referencedDomainName, ref int cbReferencedDomainName, out int use ); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] public static extern bool LookupAccountName( [In,MarshalAs(UnmanagedType.LPTStr)] string systemName, [In,MarshalAs(UnmanagedType.LPTStr)] string accountName, IntPtr sid, ref int cbSid, StringBuilder referencedDomainName, ref int cbReferencedDomainName, out int use); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] internal static extern bool ConvertSidToStringSid( IntPtr sid, [In,Out,MarshalAs(UnmanagedType.LPTStr)] ref string pStringSid); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] internal static extern bool ConvertStringSidToSid( [In, MarshalAs(UnmanagedType.LPTStr)] string pStringSid, ref IntPtr sid);

GetSid(string name)

public static string GetSid(string name) { IntPtr _sid = IntPtr.Zero; //pointer to binary form of SID string. int _sidLength = 0; //size of SID buffer. int _domainLength = 0; //size of domain name buffer. int _use; //type of object. //stringBuilder for domain name. StringBuilder _domain = new StringBuilder(); int _error = 0; string _sidString = ""; //first call of the function only returns the size //of buffers (SID, domain name) LookupAccountName(null, name, _sid, ref _sidLength, _domain, ref _domainLength, out _use); _error = Marshal.GetLastWin32Error(); //error 122 (The data area passed to a system call is too small) // normal behaviour. if (_error != 122) { throw(new Exception(new Win32Exception(_error).Message)); } else { //allocates memory for domain name _domain = new StringBuilder(_domainLength); //allocates memory for SID _sid = Marshal.AllocHGlobal(_sidLength); bool _rc = LookupAccountName(null, name, _sid, ref _sidLength, _domain, ref _domainLength, out _use); if (_rc == false) { _error = Marshal.GetLastWin32Error(); Marshal.FreeHGlobal(_sid); throw(new Exception(new Win32Exception(_error).Message)); } else { // converts binary SID into string _rc = ConvertSidToStringSid(_sid, ref _sidString); if (_rc == false) { _error = Marshal.GetLastWin32Error(); Marshal.FreeHGlobal(_sid); throw(new Exception(new Win32Exception(_error).Message)); } else { Marshal.FreeHGlobal(_sid); return _sidString; } } } }

GetName(string sid)

public static string GetName(string sid) { IntPtr _sid = IntPtr.Zero; //pointer to binary form of SID string. int _nameLength = 0; //size of object name buffer int _domainLength = 0; //size of domain name buffer int _use; //type of object StringBuilder _domain = new StringBuilder(); //domain name variable int _error = 0; StringBuilder _name = new StringBuilder(); //object name variable //converts SID string into the binary form bool _rc0 = ConvertStringSidToSid(sid, ref _sid); if (_rc0 == false) { _error = Marshal.GetLastWin32Error(); Marshal.FreeHGlobal(_sid); throw(new Exception(new Win32Exception(_error).Message)); } //first call of method returns the size of domain name //and object name buffers bool _rc = LookupAccountSid(null, _sid, _name, ref _nameLength, _domain, ref _domainLength, out _use); _domain = new StringBuilder(_domainLength); //allocates memory for domain name _name = new StringBuilder(_nameLength); //allocates memory for object name _rc = LookupAccountSid(null, _sid, _name, ref _nameLength, _domain, ref _domainLength, out _use); if (_rc == false) { _error = Marshal.GetLastWin32Error(); Marshal.FreeHGlobal(_sid); throw(new Exception(new Win32Exception(_error).Message)); } else { Marshal.FreeHGlobal(_sid); return _domain.ToString() + "\\" + _name.ToString(); } }

links:
http://www.codeproject.com/cs/library/sidtranslator.asp
http://support.microsoft.com/kb/157234