public PrincipalContext GetContext(string name, NetCred credentials, ContextOptions contextOptions)
{
string contextName = name;
string userName = null;
bool explicitCreds = false;
if (credentials != null && credentials.UserName != null)
{
if (credentials.Domain != null)
{
userName = credentials.Domain + "\\" + credentials.UserName;
}
else
{
userName = credentials.UserName;
}
explicitCreds = true;
}
else
{
userName = Utils.GetNT4UserName();
}
GlobalDebug.WriteLineIf(
GlobalDebug.Info,
"SDSCache",
"GetContext: looking for context for server {0}, user {1}, explicitCreds={2}, options={3}",
name,
userName,
explicitCreds.ToString(),
contextOptions.ToString());
if (!_isSAM)
{
// Determine the domain DNS name
// DS_RETURN_DNS_NAME | DS_DIRECTORY_SERVICE_REQUIRED | DS_BACKGROUND_ONLY
int flags = unchecked ((int)(0x40000000 | 0x00000010 | 0x00000100));
UnsafeNativeMethods.DomainControllerInfo info = Utils.GetDcName(null, contextName, null, flags);
contextName = info.DomainName;
}
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: final contextName is " + contextName);
ManualResetEvent contextReadyEvent = null;
while (true)
{
Hashtable credTable = null;
PrincipalContext ctx = null;
// Wait for the PrincipalContext to be ready
if (contextReadyEvent != null)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: waiting");
contextReadyEvent.WaitOne();
}
contextReadyEvent = null;
lock (_tableLock)
{
CredHolder credHolder = (CredHolder)_table[contextName];
if (credHolder != null)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: found a credHolder for " + contextName);
credTable = (explicitCreds ? credHolder.explicitCreds : credHolder.defaultCreds);
Debug.Assert(credTable != null);
object o = credTable[userName];
if (o is Placeholder)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: credHolder for " + contextName + " has a Placeholder");
// A PrincipalContext is currently being constructed by another thread.
// Wait for it.
contextReadyEvent = ((Placeholder)o).contextReadyEvent;
continue;
}
WeakReference refToContext = o as WeakReference;
if (refToContext != null)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: refToContext is non-null");
ctx = (PrincipalContext)refToContext.Target; // null if GC'ed
// If the PrincipalContext hasn't been GCed or disposed, use it.
// Otherwise, we'll need to create a new one
if (ctx != null && ctx.Disposed == false)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: using found refToContext");
return(ctx);
}
else
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: refToContext is GCed/disposed, removing");
credTable.Remove(userName);
}
}
}
// Either credHolder/credTable are null (no contexts exist for the contextName), or credHolder/credTable
// are non-null (contexts exist, but none for the userName). Either way, we need to create a PrincipalContext.
if (credHolder == null)
{
GlobalDebug.WriteLineIf(
GlobalDebug.Info,
"SDSCache",
"GetContext: null credHolder for " + contextName + ", explicitCreds=" + explicitCreds.ToString());
// No contexts exist for the contextName. Create a CredHolder for the contextName so we have a place
// to store the PrincipalContext we'll be creating.
credHolder = new CredHolder();
_table[contextName] = credHolder;
credTable = (explicitCreds ? credHolder.explicitCreds : credHolder.defaultCreds);
}
// Put a placeholder on the contextName/userName slot, so that other threads that come along after
// we release the tableLock know we're in the process of creating the needed PrincipalContext and will wait for us
credTable[userName] = new Placeholder();
}
// Now we just need to create a PrincipalContext for the contextName and credentials
GlobalDebug.WriteLineIf(
GlobalDebug.Info,
"SDSCache",
"GetContext: creating context, contextName=" + contextName + ", options=" + contextOptions.ToString());
ctx = new PrincipalContext(
(_isSAM ? ContextType.Machine : ContextType.Domain),
contextName,
null,
contextOptions,
credentials?.UserName,
credentials?.Password
);
lock (_tableLock)
{
Placeholder placeHolder = (Placeholder)credTable[userName];
// Replace the placeholder with the newly-created PrincipalContext
credTable[userName] = new WeakReference(ctx);
// Signal waiting threads to continue. We do this after inserting the PrincipalContext
// into the table, so that the PrincipalContext is ready as soon as the other threads wake up.
// (Actually, the order probably doesn't matter, since even if we did it in the
// opposite order and the other thread woke up before we inserted the PrincipalContext, it would
// just block as soon as it tries to acquire the tableLock that we're currently holding.)
bool f = placeHolder.contextReadyEvent.Set();
Debug.Assert(f);
}
return(ctx);
}
}
public PrincipalContext GetContext(string name, NetCred credentials, ContextOptions contextOptions)
{
string contextName = name;
string userName = null;
bool explicitCreds = false;
if (credentials != null && credentials.UserName != null)
{
if (credentials.Domain != null)
userName = credentials.Domain + "\\" + credentials.UserName;
else
userName = credentials.UserName;
explicitCreds = true;
}
else
{
userName = Utils.GetNT4UserName();
}
GlobalDebug.WriteLineIf(
GlobalDebug.Info,
"SDSCache",
"GetContext: looking for context for server {0}, user {1}, explicitCreds={2}, options={3}",
name,
userName,
explicitCreds.ToString(),
contextOptions.ToString());
if (!_isSAM)
{
// Determine the domain DNS name
// DS_RETURN_DNS_NAME | DS_DIRECTORY_SERVICE_REQUIRED | DS_BACKGROUND_ONLY
int flags = unchecked((int)(0x40000000 | 0x00000010 | 0x00000100));
UnsafeNativeMethods.DomainControllerInfo info = Utils.GetDcName(null, contextName, null, flags);
contextName = info.DomainName;
}
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: final contextName is " + contextName);
ManualResetEvent contextReadyEvent = null;
while (true)
{
Hashtable credTable = null;
PrincipalContext ctx = null;
// Wait for the PrincipalContext to be ready
if (contextReadyEvent != null)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: waiting");
contextReadyEvent.WaitOne();
}
contextReadyEvent = null;
lock (_tableLock)
{
CredHolder credHolder = (CredHolder)_table[contextName];
if (credHolder != null)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: found a credHolder for " + contextName);
credTable = (explicitCreds ? credHolder.explicitCreds : credHolder.defaultCreds);
Debug.Assert(credTable != null);
object o = credTable[userName];
if (o is Placeholder)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: credHolder for " + contextName + " has a Placeholder");
// A PrincipalContext is currently being constructed by another thread.
// Wait for it.
contextReadyEvent = ((Placeholder)o).contextReadyEvent;
continue;
}
WeakReference refToContext = o as WeakReference;
if (refToContext != null)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: refToContext is non-null");
ctx = (PrincipalContext)refToContext.Target; // null if GC'ed
// If the PrincipalContext hasn't been GCed or disposed, use it.
// Otherwise, we'll need to create a new one
if (ctx != null && ctx.Disposed == false)
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: using found refToContext");
return ctx;
}
else
{
GlobalDebug.WriteLineIf(GlobalDebug.Info, "SDSCache", "GetContext: refToContext is GCed/disposed, removing");
credTable.Remove(userName);
}
}
}
// Either credHolder/credTable are null (no contexts exist for the contextName), or credHolder/credTable
// are non-null (contexts exist, but none for the userName). Either way, we need to create a PrincipalContext.
if (credHolder == null)
{
GlobalDebug.WriteLineIf(
GlobalDebug.Info,
"SDSCache",
"GetContext: null credHolder for " + contextName + ", explicitCreds=" + explicitCreds.ToString());
// No contexts exist for the contextName. Create a CredHolder for the contextName so we have a place
// to store the PrincipalContext we'll be creating.
credHolder = new CredHolder();
_table[contextName] = credHolder;
credTable = (explicitCreds ? credHolder.explicitCreds : credHolder.defaultCreds);
}
// Put a placeholder on the contextName/userName slot, so that other threads that come along after
// we release the tableLock know we're in the process of creating the needed PrincipalContext and will wait for us
credTable[userName] = new Placeholder();
}
// Now we just need to create a PrincipalContext for the contextName and credentials
GlobalDebug.WriteLineIf(
GlobalDebug.Info,
"SDSCache",
"GetContext: creating context, contextName=" + contextName + ", options=" + contextOptions.ToString());
ctx = new PrincipalContext(
(_isSAM ? ContextType.Machine : ContextType.Domain),
contextName,
null,
contextOptions,
(credentials != null ? credentials.UserName : null),
(credentials != null ? credentials.Password : null)
);
lock (_tableLock)
{
Placeholder placeHolder = (Placeholder)credTable[userName];
// Replace the placeholder with the newly-created PrincipalContext
credTable[userName] = new WeakReference(ctx);
// Signal waiting threads to continue. We do this after inserting the PrincipalContext
// into the table, so that the PrincipalContext is ready as soon as the other threads wake up.
// (Actually, the order probably doesn't matter, since even if we did it in the
// opposite order and the other thread woke up before we inserted the PrincipalContext, it would
// just block as soon as it tries to acquire the tableLock that we're currently holding.)
bool f = placeHolder.contextReadyEvent.Set();
Debug.Assert(f == true);
}
return ctx;
}
}
